Degradable porous foam material as well as preparation method and application thereof

Abstract

The invention provides a degradable porous foam material as well as a preparation method and application thereof. The degradable porous foam material is prepared from raw materials including an oil-phase mixture and a water-phase mixture, the oil phase mixture comprises acrylated polypropylene carbonate, a photosensitive cross-linking agent and a surfactant; the photosensitive cross-linking agent comprises a diacrylate compound containing an o-nitrobenzyl ester structure; the aqueous phase mixture includes water and an electrolyte. According to the degradable porous foam material provided by the invention, all the components in the preparation raw materials are synergistically compounded, especially the acrylic polypropylene carbonate and the NBDA photosensitive cross-linking agent are introduced, so that the prepared porous foam material has photo-biological synergistic degradability, and is good in biocompatibility, non-toxic and harmless.

Description

[0001] This application claims priority to patent application number 2025117723769 (the earlier application was filed on November 28, 2025, and is entitled "A biodegradable porous foam material and its preparation method and application"). Technical Field

[0002] This invention belongs to the field of materials technology and relates to a biodegradable porous foam material, its preparation method, and its application. Background Technology

[0003] High internal phase emulsion (HIPE) is an emulsion system with a dispersed phase volume fraction greater than 74%. Due to its unique structure and properties, it shows great application potential in materials science, biomedicine, cosmetics, and other fields. Porous foam materials made from HIPE can also be used in daily chemical hygiene products, such as sanitary napkins and dressings, with advantages such as absorption, flow conduction, water retention, anti-backflow, or slow release. However, the degradability of porous foam materials made from traditional HIPE is limited, requiring chemical modification or biological methods to promote degradation. Biodegradable PPC (polypropylene carbonate), as a representative of bio-based biodegradable polymers, is synthesized from carbon dioxide and propylene oxide. The large number of ester groups in its molecular chain endows it with excellent microbial degradability, and the final products are harmless carbon dioxide and water. However, PPC has poor thermal stability (glass transition temperature of about 25°C), a narrow processing window (140-160°C), and its degradation rate is significantly affected by the propylene oxide chain segment content.

[0004] Photodegradable materials utilize photosensitizers or photosensitive groups to absorb ultraviolet light, triggering molecular chain breakage. The degradation rate is controlled by light intensity and material thickness. The porous structure provides a high specific surface area loading platform for functional components (such as photosensitizers and nanocatalysts). For example, embedding TiO2 photocatalytic particles into the pore walls of PolyHIPE can achieve synergistic effects of photodegradation and adsorption, improving the removal efficiency of organic pollutants. Furthermore, pore connectivity promotes mass transport, making it suitable for drug controlled-release systems or microbial immobilization carriers. However, physically doped photosensitizers suffer from problems such as easy migration or uneven distribution, leading to uneven degradation, and single degradation methods are limited by environmental constraints.

[0005] Therefore, developing non-toxic, harmless, photo-biodegradable PPC substrates to prepare W / O PolyHIPEs is of great significance for expanding the application of polymeric materials and improving their degradation safety performance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a biodegradable porous foam material, its preparation method, and its applications. This invention integrates technologies from three major fields: polymer synthesis (PPC modification), photochemistry (photolysis of o-nitrobenzyl ester), and materials engineering (HIPE templates). This solves the problems of single function and uncontrollable degradation in traditional PPC materials. During the preparation of PolyHIPEs, diacrylate compounds containing o-nitrobenzyl ester structures are chemically bonded into the PPC substrate as crosslinking nodes, establishing stable covalent connections and avoiding small molecule migration issues. The resulting porous foam material exhibits photo-biological synergistic degradation properties, and the synergistic effect of both enables complete degradation of the porous foam material, improving its controllable degradation and environmental adaptability.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a biodegradable porous foam material, wherein the raw materials for preparing the biodegradable porous foam material include an oil phase mixture and an aqueous phase mixture;

[0009] The oil phase mixture includes acrylated polypropylene carbonate (PPC-AC), a photosensitive crosslinking agent, and a surfactant;

[0010] The photosensitive crosslinking agent includes diacrylate compounds containing an o-nitrobenzyl ester structure;

[0011] The aqueous mixture comprises water and electrolytes.

[0012] This invention is the first to introduce diacrylate compounds containing o-nitrobenzyl ester structure as photosensitive crosslinking agents into PPC groups to prepare PolyHIPEs. The resulting porous foam material possesses controllability, spatiotemporal precision, and biocompatibility, as detailed below:

[0013] 1. Chemical bonding:

[0014] By chemically bonding diacrylate compounds containing o-nitrobenzyl ester structure as crosslinking nodes, a stable covalent bond was established in the PPC substrate, avoiding the problem of small molecule migration (reducing the amount of emulsifier used); low-temperature photopolymerization solved the problem of poor thermal stability of PPC.

[0015] 2. Photo-biological synergistic degradation:

[0016] When exposed to light, ultraviolet light triggers the breakage of the main chain; when there is no light, microbial enzymatic hydrolysis occurs. The synergistic effect of these two processes enables the porous foam material to be completely degraded (the photolysis products are further decomposed by microorganisms into CO2 and H2O, leaving no residue).

[0017] 3. Degradation of spatiotemporal precision:

[0018] (1) Photocontrolled degradation enables precise control of porous structures, such as: patterned degradation (e.g., microfluidic processing), where the irradiation area is locally controlled using photomask technology, preserving the structure in high-ν regions and rapidly dissolving in low-ν regions; remote, time-triggered degradation (e.g., tissue scaffolds), combined with two-photon excitation (wavelength 800 nm): focused laser penetrates deep into the material, breaking only the target layer NBDA (accuracy ±5 μm); or ν = 1.8 × 10 -3 mol / cm 3 After 5 hours of light exposure, it achieves 50% weight loss, and phased degradation is achieved through multiple irradiations.

[0019] (2) Rapid response: After 2 hours of irradiation with 365nm ultraviolet light, the ester bonds of diacrylate compounds containing o-nitrobenzyl ester structure break, and the crosslinking density decreases by 70% (while the molecular weight of PPC material alone decreases by only 85% after 5 days of light irradiation).

[0020] (3) Adjustable degradation rate: The photolysis efficiency can be adjusted by the degree of crosslinking of diacrylate compounds containing o-nitrobenzyl ester structure. The light intensity, wavelength and irradiation time can be precisely controlled to achieve on-demand degradation at the second to hour level.

[0021] (4) Applicability to deep tissues: Degradation is triggered by near-infrared light (700-1000nm), and it can penetrate to a depth of centimeters, making it suitable for in vivo applications (such as bone repair scaffolds).

[0022] 4. Good compatibility:

[0023] The biodegradable porous foam material provided by this invention has both high porosity and mechanical adjustability, making it suitable for load-bearing supports or flexible carriers; the emulsion supports 3D printing, custom porous materials, etc.

[0024] Preferably, the acrylated polypropylene carbonate is prepared by the following method:

[0025] (1) Polypropylene carbonate (PPC), acetic anhydride and pyridine are mixed and refluxed to obtain polypropylene carbonate-acetic anhydride;

[0026] (2) The polypropylene carbonate-anhydride obtained in step (1) is mixed with an organic solvent, and then 2-aminoethylacrylamide hydrochloride and a catalyst are added. The reaction introduces terminal acryloyl groups (grafting rate > 85%). After post-treatment, the acrylic polypropylene carbonate is obtained.

[0027] This invention grafts 2-aminoethylacrylamide onto the end of a PPC chain via an amidation reaction to form PPC-AC (acrylated PPC). The acryloyl group provides controllable crosslinking points: the carbon-carbon double bond (C=C) of the acryloyl group can undergo free radical copolymerization with the diacrylate group of NBDA under ultraviolet light initiation to form a three-dimensional network crosslinked structure; the modified PPC-AC is light-cured at room temperature without thermal damage.

[0028] Preferably, the polypropylene carbonate in step (1) has a weight-average molecular weight > 800,000, such as 820,000, 830,000, 850,000, 900,000, 930,000, 950,000, etc.

[0029] Preferably, the intrinsic viscosity of the polypropylene carbonate in step (1) is >3.5 dL / g, such as 3.6 dL / g, 3.8 dL / g, 4 dL / g, 4.2 dL / g, 4.5 dL / g, 5 dL / g, etc.

[0030] Preferably, the mass ratio of polypropylene carbonate to acetic anhydride in step (1) is 1:(5~10), for example 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, etc.

[0031] Preferably, the mass ratio of polypropylene carbonate to pyridine in step (1) is 1:(1~6), for example 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, etc.

[0032] Preferably, the reflux reaction time in step (1) is 20 to 30 hours, such as 20 hours, 22 hours, 24 hours, 25 hours, 26 hours, 28 hours, 30 hours, etc.

[0033] Preferably, the reflux reaction in step (1) is carried out under the protection of an inert gas.

[0034] Preferably, the inert gas includes nitrogen.

[0035] Preferably, the organic solvent in step (2) includes N,N-dimethylformamide (DMF).

[0036] Preferably, in step (2), the molar ratio of polypropylene carbonate-anhydride to 2-aminoethylacrylamide hydrochloride is 1:(1~1.5), for example 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.

[0037] Preferably, the catalyst in step (2) comprises 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0038] Preferably, in step (2), the amount of the catalyst is 1~2 eq, for example, 1 eq, 1.2 eq, 1.4 eq, 1.5 eq, 1.6 eq, 1.8 eq, 2 eq, etc., based on the amount of polypropylene carbonate-anhydride used being 1 mol.

[0039] Preferably, the reaction temperature in step (2) is 50~70℃, for example 50℃, 55℃, 60℃, 65℃, 70℃, etc., and the reaction time is 5~10h, for example 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0040] Preferably, the post-processing in step (2) includes precipitation, filtration, and drying.

[0041] Preferably, the photosensitive crosslinking agent comprises 4,5-bis(dodecyloxy-2-nitro-1,3-phenylene diacrylate) (NBDA).

[0042] This invention uses 4,5-bis(dodecyloxy-2-nitro-1,3-phenylene diacrylate) (NBDA) as a photosensitive crosslinking agent, which has the following advantages:

[0043] (1) Synergistic effect of dialkoxy substitution:

[0044] The electron-donating effect (+I effect) of 4,5-bisdodecyloxy group and the electron-withdrawing effect (-I effect) of nitro group form an intramolecular electron push-pull system, which increases the photolysis quantum yield to 0.42 (compared to only 0.28 for monosubstituted o-nitrobenzyl ester).

[0045] (2) Diacrylate configuration:

[0046] Two acryloyl groups (-OCOCH=CH2) serve as crosslinking points, copolymerizing with the acrylamide groups of PPC-AC to form a three-dimensional network; during photodegradation, the diester bonds break simultaneously, achieving efficient disintegration of the crosslinking points (a single break can sever two polymer chains).

[0047] Preferably, the 4,5-bis(dodecyloxy-2-nitro-1,3-phenylenediacrylate) is prepared by the following method:

[0048] (I) Etherification: 4,5-dihydroxy-2-nitrobenzaldehyde, bromododecane, an alkaline substance, and an organic solvent are mixed and reacted to obtain 4,5-bisdodecyloxy-2-nitrobenzaldehyde;

[0049] (II) Reduction: The 4,5-bisdodecyloxy-2-nitrobenzaldehyde obtained in step (I) is mixed with an organic solvent, and then sodium borohydride (NaBH4) is added. The reaction is carried out to obtain 4,5-bisdodecyloxy-2-nitrobenzaldehyde.

[0050] (III) Esterification: Acryloyl chloride, 4,5-bisdodecyloxy-2-nitrobenzyl alcohol obtained in step (II), organic solvent and catalyst are mixed, reacted, and post-treated to obtain the 4,5-bisdodecyloxy-2-nitro-1,3-phenyl diacrylate.

[0051] Preferably, the molar ratio of 4,5-dihydroxy-2-nitrobenzaldehyde to bromododecane in step (I) is 1:(1~3), for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc.

[0052] Preferably, the alkaline substance in step (I) includes potassium carbonate (K2CO3).

[0053] Preferably, the mass ratio of 4,5-dihydroxy-2-nitrobenzaldehyde to the alkaline substance in step (I) is 1:(1~5), for example, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, etc.

[0054] Preferably, the organic solvent in step (I) includes N,N-dimethylformamide (DMF).

[0055] Preferably, the reaction temperature in step (I) is 50~70℃, such as 50℃, 55℃, 60℃, 65℃, 70℃, etc., and the reaction time is 20~30h, such as 20h, 22h, 24h, 25h, 26h, 28h, 30h, etc.

[0056] Preferably, the organic solvent in step (II) comprises tetrahydrofuran (THF) and / or methanol.

[0057] Preferably, the organic solvent in step (II) comprises tetrahydrofuran and methanol in a volume ratio of 1:(0.5~2) (e.g., 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, etc.).

[0058] Preferably, in step (II), the molar ratio of 4,5-bis(dodecyloxy-2-nitrobenzaldehyde) to sodium borohydride is 1:(2~4), for example 1:2, 1:2.5, 1:3, 1:3.5, 1:4, etc.

[0059] Preferably, the addition of sodium borohydride in step (II) specifically includes adding sodium borohydride in batches under ice bath conditions.

[0060] Preferably, the temperature of the reaction in step (II) is -10~0℃, for example -10℃, -8℃, -5℃, -3℃, 0℃, etc., and the reaction time is 20~40min, for example 20min, 25min, 30min, 35min, 40min, etc.

[0061] Preferably, in step (III), the molar ratio of 4,5-bisdodecoxy-2-nitrobenzyl alcohol to acryloyl chloride is 1:(2~4), for example 1:2, 1:2.5, 1:3, 1:3.5, 1:4, etc.

[0062] Preferably, the solvent in step (III) comprises dichloromethane.

[0063] Preferably, the catalyst in step (III) comprises 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0064] Preferably, in step (III), based on the amount of 4,5-bisdodecyloxy-2-nitrobenzyl alcohol used being 1 mol, the amount of catalyst used is 0.05~0.2 eq, for example 0.05 eq, 0.06 eq, 0.08 eq, 0.1 eq, 0.12 eq, 0.14 eq, 0.15 eq, 0.16 eq, 0.18 eq, 0.2 eq, etc.

[0065] Preferably, the reaction temperature in step (III) is 20~30℃, such as 20℃, 25℃, 30℃, etc., and the reaction time is 10~20h, such as 10h, 12h, 14h, 15h, 16h, 18h, 20h, etc.

[0066] Preferably, the reaction in step (III) is carried out under light-protected conditions.

[0067] Preferably, the post-processing in step (III) includes purification.

[0068] Preferably, the surfactant comprises DTPA (diethylenetriaminepentaacetic acid) modified didodecyl benzyl ester.

[0069] Preferably, the DTPA-modified didodecyl benzyl ester is prepared by the following method:

[0070] Diethylenetriaminepentaacetic acid dianhydride and solvent were mixed, then a dodecyl bromide derivative was added, followed by the addition of a catalyst, reaction, and post-treatment to obtain the DTPA-modified dodecyl benzyl ester.

[0071] Preferably, the solvent comprises anhydrous N,N-dimethylformamide.

[0072] Preferably, the structural formula of the didodecyl bromide derivative is as follows: .

[0073] Preferably, the mass ratio of the diethylenetriaminepentaacetic acid dianhydride to the didodecyl brominated derivative is 1:(1~2), for example, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, etc.

[0074] Preferably, the catalyst comprises 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0075] Preferably, based on 1 mol of the dodecyl brominated derivative, the amount of the catalyst is 0.1~0.3 eq, for example 0.1 eq, 0.2 eq, 0.3 eq, etc.

[0076] Preferably, the reaction temperature is 30~80℃, such as 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, etc., and the reaction time is 1~2h, such as 1h, 1.5h, 2h, etc.

[0077] Preferably, the reaction is carried out under the protection of an inert gas.

[0078] Preferably, the post-processing includes centrifugation and column chromatography separation.

[0079] The surfactant DTPA used in this invention can react with Gd 3+ Complexation endows the material with MRI imaging capabilities, integrating MRI imaging and degradation functions, and the material can be extended to the field of integrated diagnosis and treatment; DTPA-DDB (diethylenetriaminepentaacetic acid-bis(dodecylbenzyl)ester) has no absorption at 365 nm and does not compete for ultraviolet light, ensuring the photolysis efficiency of NBDA (quantum yield remains at 0.42); DTPA hydrolyzes into amino acid derivatives, and the degradation products are safe.

[0080] Preferably, based on the total mass of the oil phase mixture as 100%, the content of the acrylated polypropylene carbonate is 50% to 80% (e.g., 50%, 52%, 54%, 55%, 56%, 58%, 60%, 62%, 64%, 65%, 66%, 68%, 70%, 72%, 74%, 75%, 76%, 78%, 80%, etc.), the content of the photosensitive crosslinking agent is 10% to 30% (e.g., 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, etc.), and the content of the surfactant is 5% to 20% (e.g., 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, etc.).

[0081] Preferably, the electrolyte comprises calcium chloride. The electrolyte is added to prevent droplet coalescence.

[0082] Preferably, the concentration of the electrolyte in the aqueous mixture is 0.05~0.7 mol / L, for example 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.7 mol / L, etc.

[0083] Preferably, the volume ratio of the oil phase mixture to the water phase mixture is 1:(5~30), where 5~30 can be, for example, 5, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, etc.

[0084] In a second aspect, the present invention provides a method for preparing a biodegradable porous foam material as described in the first aspect, the method comprising the following steps:

[0085] (a) Acrylate polypropylene carbonate, photosensitive crosslinking agent and surfactant are mixed to obtain an oil phase mixture;

[0086] (b) Water and electrolyte are mixed to obtain an aqueous mixture;

[0087] (c) Mix the aqueous phase mixture with the oil phase mixture and homogenize to obtain a high internal phase emulsion;

[0088] (d) The high internal phase emulsion is added to a mold, photocured, and post-treated to obtain the porous foam material.

[0089] Preferably, the mixing temperature in step (a) is 50~70°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, etc.

[0090] Preferably, the mixing method in step (c) includes mechanical stirring.

[0091] Preferably, the mixing speed in step (c) is 800~1200 rpm, such as 800 rpm, 850 rpm, 900 rpm, 950 rpm, 1000 rpm, 1050 rpm, 1100 rpm, 1150 rpm, 1200 rpm, etc., and the mixing time is 5~15 min, such as 5 min, 6 min, 8 min, 10 min, 12 min, 15 min, etc.

[0092] Preferably, the homogenization speed in step (c) is 1500~2000 rpm, such as 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm, 2000 rpm, etc., and the homogenization time is 2~8 min, such as 2 min, 3 min, 5 min, 6 min, 8 min, etc.

[0093] Preferably, the wavelength of photocuring in step (d) is 300~400nm, such as 300nm, 365nm, 400nm, etc., and the intensity of photocuring is 10~20mW / cm. 2 For example, 10mW / cm 2 15mW / cm 2 20mW / cm 2 The photocuring time is 20-40 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, etc. Photocuring causes the reactants to react and form a free radical polymerized solidified network.

[0094] Preferably, the photocuring in step (d) is carried out under inert gas protection.

[0095] Preferably, the inert gas includes nitrogen.

[0096] Preferably, the post-processing in step (d) includes washing and drying.

[0097] Preferably, the detergent used in the washing process includes methanol and / or ethanol. The purpose of washing is to remove residual aqueous phase.

[0098] Preferably, the drying includes vacuum drying or drying using supercritical CO2.

[0099] Thirdly, the present invention provides an application of the biodegradable porous foam material as described in the first aspect in tissue engineering scaffolds, targeted drug delivery systems, environmentally friendly adsorbent materials, and daily chemical hygiene products.

[0100] Specifically, the applications of the biodegradable porous foam material provided by this invention are as follows:

[0101] 1. Tissue engineering scaffold

[0102] (1) Dynamic degradation matching tissue growth:

[0103] Initial stage: High porosity (pore size 100-300μm) promotes cell migration;

[0104] Repair period: Localized ultraviolet irradiation expands the pores (photolysis increases the pore size by 50%), making room for new tissue;

[0105] Later stage: The PPC backbone is broken down by cellular esterases, avoiding the need for a second surgery to remove it.

[0106] To achieve simultaneous regulation of degradation and new tissue formation.

[0107] (2) Dual antibacterial and osteogenic functions:

[0108] The photolysis products inhibit Staphylococcus aureus (inhibition rate 99%).

[0109] Porous materials loaded with BMP-2 growth factor promote bone defect repair (rabbit femoral experiments showed a 30% increase in healing speed).

[0110] 2. Targeted drug delivery system

[0111] Porous structures encapsulate hydrophobic drugs (such as paclitaxel), with light-triggered local release; DTPA-Gd 3+ Enables MRI monitoring of the release process.

[0112] Application scenarios: interventional tumor treatment (such as hepatic artery embolization) to reduce systemic toxic side effects.

[0113] 3. Environmentally friendly adsorption materials

[0114] Oil-water separation: Hydrophobic surfaces (contact angle > 140°) adsorb floating oil at sea. After saturation, light exposure causes the material to disintegrate, allowing for oil recovery and preventing secondary pollution.

[0115] 4. Specifically, the biodegradable porous foam material can be used in the field of sanitary napkins, dressings, and other daily chemical hygiene products. Using one or more layers of biodegradable porous foam material, made from a high internal phase emulsion with the same or different pore sizes, as the core of sanitary napkins, dressings, and other daily chemical hygiene products, its high porosity, high connectivity, and controllable pore size enable absorption, drainage, water retention, anti-backflow, or slow release of liquids such as moisture, menstrual blood, blood, body fluids, and nutrients. This gives the product excellent properties such as thinness, dryness, long-lasting effect, and slow release.

[0116] Compared with the prior art, the present invention has the following beneficial effects:

[0117] The biodegradable porous foam material provided by this invention, through the synergistic compounding of various components in the raw materials, especially the introduction of acrylated polypropylene carbonate and NBDA photosensitive crosslinking agent, enables the prepared porous foam material to possess photo-biosynergistic degradability, good biocompatibility, and is non-toxic and harmless. The biodegradable porous foam material provided by this invention has a porosity of 88%~92%, an average pore size of 52~65μm (suitable for cell migration and material transport), and a compressive modulus of 9.5~13.5MPa (meeting the load-bearing requirements of tissue engineering scaffolds); degradation performance: mineralization rate ≥85% after 45 days, mineralization rate ≥93% after 60 days, weight-average molecular weight of residual polymer <100, and complete degradation without residue. Attached Figure Description

[0118] Figure 1 The image shows a SEM image of the biodegradable porous foam material provided in Example 1.

[0119] Figure 2The mineralization rate of the porous foam materials provided in Example 1, Comparative Examples 4 and 5 over 45 days is shown in the graph. Detailed Implementation

[0120] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0121] Unless otherwise specified, the sources of some of the raw materials used in the preparation examples and embodiments of this invention are as follows:

[0122] Polypropylene carbonate (PPC), purchased from Aladdin;

[0123] Acetic anhydride, 95%, purchased from Aladdin;

[0124] 4,5-Dihydroxy-2-nitrobenzaldehyde, 95%, purchased from: Maclean's Reagents;

[0125] Bromododecane, 98%, purchased from Aladdin;

[0126] N,N-Dimethylformamide, 99.5%, purchased from: Maclean's;

[0127] Diethylenetriaminepentaacetic anhydride, 98%, purchased from Aladdin.

[0128] Preparation Example 1

[0129] This preparation example provides an acrylated polypropylene carbonate (PPC-AC), the preparation method of which includes the following steps:

[0130] PPC (100 g, Mw=850 kDa) was added to a three-necked flask with acetic anhydride (555 mL) and pyridine (300 mL) and refluxed for 24 h under nitrogen protection. The solvent was removed by vacuum distillation to obtain PPC-anhydride (pale yellow solid). PPC-anhydride was dissolved in DMF (500 mL), and 2-aminoethylacrylamide hydrochloride (35.2 g) and DBU (45.6 mL) were added. The mixture was stirred at 60 °C for 8 h. The reaction solution was poured into ice-cold ether to precipitate the precipitate. After filtration, the precipitate was dried under vacuum to obtain PPC-AC (grafting rate 87.3%, yield 91%).

[0131] Preparation Example 2

[0132] This preparation example provides a 4,5-bis(dodecyloxy-2-nitro-1,3-phenylene diacrylate) (NBDA), the preparation method of which includes the following steps:

[0133] 4,5-Dihydroxy-2-nitrobenzaldehyde (10 g) was reacted with bromododecane (42.3 g) in K2CO3 (27.6 g) / DMF (200 mL) at 60°C for 24 h. After washing with water, the mixture was subjected to column chromatography (petroleum ether:ethyl acetate = 10:1, v / v) to give 4,5-bisdodecyloxy-2-nitrobenzaldehyde (white solid, yield 85%).

[0134] 15 g of 4,5-bisdodecyloxy-2-nitrobenzaldehyde was dissolved in THF / methanol (volume ratio 1:1, 300 mL), and 4.1 g of NaBH4 was added in portions under ice bath conditions. The reaction was quenched after reacting at -5 °C for 30 min, and the mixture was extracted to obtain the alcohol intermediate (4,5-bisdodecyloxy-2-nitrobenzaldehyde).

[0135] The alcohol intermediate (12 g) and acryloyl chloride (7.2 mL) were added to anhydrous dichloromethane (150 mL) and reacted at 25°C in the dark for 12 h under the catalysis of DBU (1.2 mL). The mixture was purified by column chromatography (dichloromethane:methanol = 100:1, volume ratio) to obtain NBDA (yellow oil, yield 52%).

[0136] Preparation Example 3

[0137] This preparation example provides a DTPA-modified bis(dodecyl)benzyl ester, the preparation method of which includes the following steps:

[0138] Anhydrous N,N-dimethylformamide (DMF) (100 mL) was added to diethylenetriaminepentaacetic acid dianhydride (10.0 g), heated to 65 °C to dissolve, and then cooled to room temperature; 15.6 g of a didodecyl bromide derivative (structural formula: [insert structural formula here]) dissolved in anhydrous DMF (50 mL) was added dropwise. Then, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 0.54 g) catalyst dissolved in anhydrous DMF (10 ml) was added dropwise; the reaction was carried out at 50 °C for 1.5 h under nitrogen protection. Water was added to the reaction solution to produce a milky white liquid, and the lower layer of yellowish-brown solid was collected by centrifugation; column chromatography was used to separate the solid, and a 50:1 volume ratio of dichloromethane-methanol mixture was used as the eluent to obtain a bright yellow DTPA-modified didodecyl benzyl ester solid with a yield of 70%.

[0139] Example 1

[0140] This embodiment provides a biodegradable porous foam material, the raw materials for preparing the biodegradable porous foam material including an oil phase mixture and an aqueous phase mixture;

[0141] The oil phase mixture includes acrylated polypropylene carbonate (PPC-AC, provided in Preparation Example 1), a photosensitive crosslinking agent (NBDA, provided in Preparation Example 2), and a surfactant (DTPA-modified didodecyl benzyl ester, provided in Preparation Example 3).

[0142] The aqueous mixture comprises water and an electrolyte (CaCl2).

[0143] Wherein, based on the total mass of the oil phase mixture as 100%, the content of the acrylic polypropylene carbonate is 70%, the content of the photosensitive crosslinking agent is 20%, and the content of the surfactant is 10%;

[0144] The concentration of the electrolyte in the aqueous mixture is 0.1 mol / L;

[0145] The volume ratio of the oil phase mixture to the water phase mixture is 1:5.

[0146] The preparation method includes the following steps:

[0147] (a) Acrylate polypropylene carbonate, photosensitive crosslinking agent and surfactant are melt-mixed at 60°C to obtain an oil phase mixture, which is then cooled to 25°C;

[0148] (b) Water and electrolyte are mixed to obtain an aqueous mixture;

[0149] (c) The aqueous phase mixture was slowly added to the oil phase, mechanically stirred (1000 rpm, 10 min), and then homogenized (1800 rpm, 5 min) to obtain a W / O type HIPE, which is a high internal phase emulsion (aqueous phase volume fraction φ=83.3%, white paste, stable at 25℃ for >48 h).

[0150] (d) Inject the high internal phase emulsion into a polytetrafluoroethylene mold (10×10×0.5 cm). 3 Under N2 protection, the emulsion was irradiated with a 365 nm LED light source (10 mW / cm). 2 Free radical polymerization was initiated by soaking in ethanol for 24 h (replaced 3 times) to remove unreacted monomers; then the material was dried with supercritical CO2 (40℃, 15 MPa, 4 h) to obtain a white, lightweight porous foam material (PPC / NBDA PolyHIPE).

[0151] The SEM image of the biodegradable porous foam material provided in this embodiment is as follows: Figure 1 As shown.

[0152] Examples 2-6

[0153] The only difference from Example 1 is that the types and / or amounts of raw materials are different, as shown in Table 1.

[0154] Table 1

[0155]

[0156] Comparative Example 1

[0157] The only difference between this comparative example and Example 1 is that acrylated polypropylene carbonate (PPC-AC) is replaced with an equal weight of unmodified PPC.

[0158] Comparative Example 2

[0159] The only difference between this comparative example and Example 1 is that the photosensitive crosslinking agent (NBDA) is replaced with an equal weight of 7-hydroxycoumarin.

[0160] Comparative Example 3

[0161] The only difference between this comparative example and Example 1 is that the surfactant (DTPA-modified bis(dodecyl)benzyl ester) is replaced with an equal weight of Span 80.

[0162] Comparative Example 4 (Photodegradation only)

[0163] The only difference between this comparative example and Example 1 is that the biodegradable PPC-AC is replaced with an equal weight of a photodegradable acrylate polymer (poly(o-nitrobenzyl methacrylate) PNBMA, purchased from Aladdin).

[0164] PNBMA contains o-nitrobenzyl ester photodegradable groups, but lacks biodegradable structures such as ester groups, and can only break the main chain through light exposure.

[0165] Comparative Example 5 (Biodegradation Only)

[0166] The only difference between this comparative example and Example 1 is that the photosensitive crosslinking agent (NBDA) is replaced with an equal weight of a biodegradable crosslinking agent (1,4-butanediol diacrylate, BDDA).

[0167] BDDA contains diacrylate crosslinking groups, which can copolymerize with PPC-AC to form a network, but it has no photolytic groups and can only be enzymatically hydrolyzed by microorganisms through the ester groups of PPC-AC.

[0168] The performance of the porous foam materials provided in the embodiments and comparative examples of the present invention was tested using the following methods:

[0169] (1) Porosity: The ethanol replacement method was used: the porous foam material sample was vacuum dried at 50℃ for 12h, weighed and recorded as m1; the dried sample was immersed in anhydrous ethanol for vacuum degassing for 30min, weighed after saturation and recorded as m2; the volume V was measured by the water displacement method. ;

[0170] (2) Average pore size: The cross-section of the porous foam material was observed using a scanning electron microscope (SEM). 100 cells were selected to measure the diameter and the average pore diameter D50 was calculated.

[0171] (3) Compression modulus: The test was conducted according to ATSM D695. The porous foam material sample was cut into 10mm×10mm×5mm pieces and tested at a compression rate of 1mm / min. The stress-strain curve was obtained, and the compression modulus was calculated by taking the linear segment of strain from 2% to 8%.

[0172] (4) Biodegradation test, specifically testing the mineralization rate at 45 days and 60 days: According to the ISO 14855 composting standard, the mineralization rate of photodegradable fragments (molecular weight <2000 Da) was tested within 45 days and 60 days.

[0173] (5) Residual polymer test: The polymer and small molecule components in the degraded sample are separated by gel permeation chromatography. A molecular weight calibration curve is established using a standard (polystyrene) to quantitatively analyze the weight-average molecular weight of the residual polymer.

[0174] The performance test results are shown in Table 2.

[0175] Table 2

[0176]

[0177] As can be seen from Table 2, the biodegradable porous foam materials provided in the embodiments of the present invention all have high porosity (88%~92%), high compressive modulus (9.5~13.5MPa), and good photo-biological synergistic degradation (45-day mineralization rate: 88%~91%, 60-day mineralization rate: 93%~96%, and the weight average molecular weight of the residual polymer is <100).

[0178] Compared with Example 1, the porosity, compressive modulus, 45-day mineralization rate, and 60-day mineralization rate of the porous foam materials provided in Comparative Examples 1-3 were significantly reduced, and the weight-average molecular weight of the residual polymer in the porous foam materials provided in Comparative Examples 1-2 was significantly increased; the 45-day and 60-day mineralization rates of the porous foam materials provided in Comparative Example 4 were significantly reduced, and the weight-average molecular weight of the residual polymer was significantly increased; the 45-day and 60-day mineralization rates of the porous foam materials provided in Comparative Example 5 were significantly reduced, and the weight-average molecular weight of the residual polymer was significantly increased.

[0179] The mineralization rate of the porous foam materials provided in Example 1, Comparative Examples 4 and 5 over 45 days is shown in the following graphs. Figure 2 As shown.

[0180] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate the biodegradable porous foam material, its preparation method, and its application. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A degradable porous foam material, characterized in that, The raw material for preparing the degradable porous foam material comprises an oil phase mixture and a water phase mixture; The oil phase mixture comprises acrylic polypropylene carbonate, a photosensitive crosslinking agent and a surfactant; The photosensitive crosslinking agent comprises a bisacrylate compound containing an o-nitrobenzyl ester structure; The water phase mixture comprises water and an electrolyte.

2. The degradable porous foam material of claim 1, wherein, The acrylic polypropylene carbonate is prepared by the following method: (1) mixing polypropylene carbonate, acetic anhydride and pyridine, and refluxing to obtain polypropylene carbonate-anhydride; (2) mixing the polypropylene carbonate-anhydride obtained in step (1) and an organic solvent, then adding 2-aminoethyl acrylamide hydrochloride and a catalyst, and reacting, and then post-treating to obtain the acrylic polypropylene carbonate.

3. The degradable porous foam material of claim 2, wherein, The weight average molecular weight of the polypropylene carbonate in step (1) is greater than 800,000; Preferably, the intrinsic viscosity of the polypropylene carbonate in step (1) is greater than 3.5 dL / g; Preferably, the mass ratio of the polypropylene carbonate to acetic anhydride in step (1) is 1:(5-10); Preferably, the mass ratio of the polypropylene carbonate to pyridine in step (1) is 1:(1-6); Preferably, the refluxing time in step (1) is 20-30 hours; Preferably, the refluxing in step (1) is carried out under inert gas protection; Preferably, the organic solvent in step (2) comprises N,N-dimethylformamide; Preferably, in step (2), the molar ratio of polypropylene carbonate-anhydride to 2-aminoethyl acrylamide hydrochloride is 1:(1-1.5); Preferably, the catalyst in step (2) comprises 1,8-diazabicyclo[5.4.0]undec-7-ene; Preferably, in step (2), the amount of the catalyst is 1-2 eq based on 1 mol of the polypropylene carbonate-anhydride; Preferably, the reaction temperature in step (2) is 50-70°C, and the reaction time is 5-10 hours; Preferably, the post-treatment in step (2) comprises precipitation, filtration and drying.

4. The degradable porous foam material of any one of claims 1-3, wherein, The photosensitive crosslinking agent comprises 4,5-bis-dodecyloxy-2-nitro-1,3-benzene diacrylate; Preferably, the 4,5-bis-dodecyloxy-2-nitro-1,3-benzene diacrylate is prepared by the following method: (I) mixing 4,5-dihydroxy-2-nitrobenzaldehyde, bromododecane, an alkaline substance and an organic solvent, and reacting to obtain 4,5-bis-dodecyloxy-2-nitrobenzaldehyde; (II) mixing the 4,5-bis-dodecyloxy-2-nitrobenzaldehyde obtained in step (I) and an organic solvent, then adding sodium borohydride, and reacting to obtain 4,5-bis-dodecyloxy-2-nitrobenzyl alcohol; (III) mixing acryloyl chloride, the 4,5-bis-dodecyloxy-2-nitrobenzyl alcohol obtained in step (II), an organic solvent and a catalyst, and reacting, and then post-treating to obtain the 4,5-bis-dodecyloxy-2-nitro-1,3-benzene diacrylate.

5. The degradable porous foam material of claim 4, wherein, The molar ratio of the 4,5-dihydroxy-2-nitrobenzaldehyde to bromododecane in step (I) is 1:(1-3). Preferably, the basic substance in step (I) comprises potassium carbonate; Preferably, the mass ratio of 4, 5-dihydroxy-2-nitrobenzaldehyde to the basic substance in step (I) is 1: (1-5) ; Preferably, the organic solvent in step (I) comprises N, N-dimethylformamide; Preferably, the temperature of the reaction in step (I) is 50-70℃, and the reaction time is 20-30h; Preferably, the organic solvent in step (II) comprises tetrahydrofuran and / or methanol; Preferably, the organic solvent in step (II) comprises tetrahydrofuran and methanol in a volume ratio of 1: (0.5-2) ; Preferably, in step (II), the molar ratio of 4, 5-didodecyloxy-2-nitrobenzaldehyde to sodium borohydride is 1: (2-4) ; Preferably, in step (II), the addition of sodium borohydride comprises adding sodium borohydride in batches under ice bath conditions; Preferably, the temperature of the reaction in step (II) is-10-0℃, and the reaction time is 20-40min; Preferably, in step (III), the molar ratio of 4, 5-didodecyloxy-2-nitrobenzyl alcohol to acryloyl chloride is 1: (2-4) ; Preferably, the solvent in step (III) comprises dichloromethane; Preferably, the catalyst in step (III) comprises 1, 8-diazabicyclo [5.4.0] undec-7-ene; Preferably, in step (III), the amount of the catalyst is 0.05-0.2eq based on 1mol of the 4, 5-didodecyloxy-2-nitrobenzyl alcohol; Preferably, the temperature of the reaction in step (III) is 20-30℃, and the reaction time is 10-20h; Preferably, the reaction in step (III) is carried out under light shielding conditions; Preferably, the post-treatment in step (III) comprises purification.

6. The degradable porous foam material of any one of claims 1-5, wherein, The surfactant comprises DTPA modified didodecyl benzyl ester; Preferably, the DTPA modified didodecyl benzyl ester is prepared by the following method: Mixing diethylenetriamine pentaacetic dianhydride and solvent, then adding didodecyl bromo derivative, then adding catalyst, reacting, post-treatment, to obtain the DTPA modified didodecyl benzyl ester; Preferably, the solvent comprises anhydrous N, N-dimethylformamide; Preferably, the didodecyl bromo derivative has the following structure: ; Preferably, the mass ratio of diethylenetriamine pentaacetic dianhydride to didodecyl bromo derivative is 1: (1-2) ; Preferably, the catalyst comprises 1, 8-diazabicyclo [5.4.0] undec-7-ene; Preferably, the amount of the catalyst is 0.1-0.3eq based on 1mol of the didodecyl bromo derivative; Preferably, the temperature of the reaction is 30-80℃, and the reaction time is 1-2h; Preferably, the reaction is carried out under inert gas protection; Preferably, the post-treatment comprises centrifugation and column chromatography separation.

7. The degradable porous foam material of any one of claims 1-6, wherein, The content of the acrylated polypropylene carbonate is 50%-80%, the content of the photosensitive crosslinking agent is 10%-30%, and the content of the surfactant is 5%-20%, based on the total mass of the oil phase mixture being 100%. Preferably, the electrolyte comprises calcium chloride; Preferably, the concentration of the electrolyte in the aqueous phase mixture is 0.05-0.7 mol / L; Preferably, the volume ratio of the oil phase mixture to the aqueous phase mixture is 1:(5-30).

8. A method of producing a degradable porous foam material as claimed in any one of claims 1 to 7, characterised in that, The preparation method comprises the following steps: (a) mixing acrylic propylene carbonate, photosensitive crosslinking agent and surfactant to obtain an oil phase mixture; (b) mixing water and electrolyte to obtain an aqueous phase mixture; (c) mixing the aqueous phase mixture and the oil phase mixture, homogenizing to obtain a high internal phase emulsion; (d) adding the high internal phase emulsion into a mold, photocuring, post-treatment to obtain the porous foam material.

9. The production method according to claim 8, characterized by, The temperature of the mixing in step (a) is 50-70℃; Preferably, the mixing in step (c) is by mechanical stirring; Preferably, the rotation speed of the mixing in step (c) is 800-1200 rpm, and the mixing time is 5-15 min; Preferably, the rotation speed of the homogenizing in step (c) is 1500-2000 rpm, and the homogenizing time is 2-8 min; Preferably, the wavelength of the light curing in step (d) is 300-400 nm, the intensity of the light curing is 10-20 mW / cm 2 , and the time of the light curing is 20-40 min. Preferably, the photocuring in step (d) is under inert gas protection; Preferably, the inert gas comprises nitrogen; Preferably, the post-treatment in step (d) comprises washing and drying; Preferably, the washing agent used in the washing comprises methanol and / or ethanol; Preferably, the drying comprises vacuum drying or drying with supercritical CO2.

10. Use of the degradable porous foam material according to any one of claims 1-7 in tissue engineering scaffolds, targeted drug delivery systems, environmental adsorption materials, daily hygiene products.

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