Pbat / lignin composite material with excellent mechanical properties and manufacturing method thereof

Abstract

The present disclosure relates to a PBAT / lignin composite material having excellent mechanical properties and a method for manufacturing the same. Specifically, the PBAT / lignin composite material according to the present disclosure is easy to process without losing the crystallinity of PBAT, maintains the physical properties of PBAT such as tensile strength and tensile strain well, and can also exhibit a UV blocking effect due to the benzene structure of lignin.

Description

Technology Field

[0001] The present disclosure relates to a PBAT / lignin composite material having excellent mechanical properties and a method for manufacturing the same.

[0002] [Explanation of government-supported R&D]

[0003] This research was conducted under the supervision of the Korea Institute of Science and Technology and supported by the Ministry of Science and ICT’s Advanced Convergence Research Project (Advanced research on the development of high-heat-resistant and high-flame-retardant materials through industrial waste upcycling and application technology for building insulation materials, Project No.: 1711201893) and the Ministry of Science and ICT’s National Research Council of Science and Technology’s Research Operation Support Project (Development of lightweight platform technology for recyclable future air mobility structural materials and components, Project No.: 1711202568). Background Technology

[0004] Due to the social issues surrounding plastic waste, various technologies regarding raw materials for biodegradable resins are being proposed. Biodegradable resin raw materials can be broadly classified into natural polymers (starch, rubber, etc.), copolymers (poly-hydroxy alkanoates, etc.), and synthetic polymers (aliphatic polyesters, PCL (Polycaprolactone), PLA (Poly Lactic Acid), PBAT (Polybutylene Adipate Terephthalate), etc.). Synthetic polymers, which allow for mass production, are widely used as raw materials for biodegradable resins.

[0005] Since these synthetic polymer-based biodegradable resins have inferior mechanical properties compared to general-purpose polymers, making them difficult to apply in various fields, technologies to improve their properties through blending or composite formation are being researched. Most existing technologies involve the composite formation of polymer raw materials using solid additives (such as CNTs, silica, and oxide particles).

[0006] PBAT, a petroleum-based biodegradable plastic, possesses excellent decomposition characteristics but has limitations in that it is more expensive than general-purpose plastics from raw materials to finished products due to the significant energy generated during the manufacturing process. Additionally, composite resins produced by blending PBAT suffer from issues such as changes in the physical properties of the existing resin, reduced processability, and decreased mechanical strength. Prior art literature

[0007] Republic of Korea Registered Patent Publication No. 10-2431676 The problem to be solved

[0008] The present disclosure aims to provide a PBAT composite material that is easy to process without losing the crystallinity of PBAT and maintains the physical properties of PBAT, such as tensile strength and tensile strain. means of solving the problem

[0009] To achieve the above objective, one embodiment of the present invention provides a PBAT / lignin composite material comprising: modified lignin in which at least one terminal hydroxyl group is substituted with a phenolic group; and polybutylene adipate terephthalate (PBAT).

[0010] In addition, one embodiment of the present invention provides a method for manufacturing a PBAT / lignin composite material comprising mixing and compounding modified lignin, in which at least one terminal hydroxyl group is substituted with a phenolic group, and polybutylene adipate terephthalate (PBAT) at a temperature of 100 to 200°C. Effects of the invention

[0011] The PBAT / lignin composite material according to the present disclosure is easy to process without losing the crystallinity of PBAT, maintains the physical properties of PBAT such as tensile strength and tensile strain well, and can also exhibit a UV blocking effect due to the benzene structure of lignin. Brief explanation of the drawing

[0012] Figures 1a and 1b show the results of measuring the thermal decomposition of PBAT / lignin composite materials as a function of temperature. (Figure 1a: Modified lignin, Figure 1b: Kraft lignin) Figures 2a and 2b show the results of mechanical strength measurements of PBAT / lignin composite materials. (Figure 2a: Modified lignin, Figure 2b: Kraft lignin) Figures 3a and 3b show the results of tensile strain measurements of PBAT / lignin composite materials. (Fig. 3a: Modified lignin, Fig. 3b: Kraft lignin) Figure 4 shows the measurement results of the UV blocking properties of the PBAT / lignin composite material. Specific details for implementing the invention

[0013] The present invention will be described in detail below.

[0014] In one aspect, the present invention may relate to a PBAT / lignin composite material.

[0015] In one embodiment, the composite material may comprise modified lignin in which at least one terminal hydroxyl group is substituted with a phenolic group; and polybutylene adipate terephthalate (PBAT).

[0016] In one embodiment, the modified lignin may be represented by the following chemical formula 1.

[0017] [Chemical Formula 1]

[0018] .

[0019] In one embodiment, the weight-average molecular weight (Mw) of the modified lignin may be 500 or more and less than 5,000. Specifically, the weight-average molecular weight (Mw) of the modified lignin may be 500 or more, 600 or more, 700 or more, 800 or more, 900 or more, 1,000 or more, 1,500 or more, 2,000 or more, 2,100 or more, 2,200 or more, 2,300 or more, 2,400 or more, 2,500 or more, 3,000 or more, 3,500 or more, 4,000 or more, or 4,500 or more, and additionally, the weight-average molecular weight (Mw) of the modified lignin may be less than 5,000, 4,500 or less, 4,000 or less, 3,500 or less, 3,000 or less, 2,500 or less, 2,400 or less, 2,300 or less, 2,200 or less, 2,000 or less, It may be 1,500 or less, 1,000 or less, 900 or less, 800 or less, 700 or less, or 600 or less.

[0020] In one embodiment, the number average molecular weight (Mn) of the modified lignin may be 100 or more and less than 1,500. Specifically, the number average molecular weight (Mn) of the modified lignin may be 100 or more, 200 or more, 300 or more, 400 or more, 500 or more, 600 or more, 700 or more, 800 or more, 900 or more, 1,000 or more, or 1,200 or more, and additionally, the number average molecular weight (Mn) of the modified lignin may be less than 1,500, 1,000 or less, 900 or less, 800 or less, 790 or less, 780 or less, 770 or less, 760 or less, 750 or less, 700 or less, 600 or less, 500 or less, 400 or less, or 300 or less.

[0021] In one embodiment, the softening point of the modified lignin may be 100 to 200°C. Specifically, the softening point of the modified lignin may be 100°C or higher, 110°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, or 190°C or higher, and additionally, the softening point of the modified lignin may be 200°C or lower, 190°C or lower, 180°C or lower, 170°C or lower, 165°C or lower, 163°C or lower, 160°C or lower, 150°C or lower, 140°C or lower, 130°C or lower, or 120°C or lower.

[0022] In one embodiment, the modified lignin may be included in an amount of 1 to 30 parts by weight relative to 100 parts by weight of the PBAT. Specifically, the modified lignin may be included in an amount of 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 12 parts by weight or more, 13 parts by weight or more, 14 parts by weight or more, 15 parts by weight or more, 16 parts by weight or more, 17 parts by weight or more, 18 parts by weight or more, 19 parts by weight or more, 20 parts by weight or more, 21 parts by weight or more, 22 parts by weight or more, 23 parts by weight or more, 24 parts by weight or more, 25 parts by weight or more, 26 parts by weight or more, 27 parts by weight or more, or 28 parts by weight or more, relative to 100 parts by weight of the PBAT; additionally, the modified lignin may be included in an amount of 30 parts by weight or less, 29 parts by weight or less, or 28 parts by weight or more, relative to 100 parts by weight of the PBAT. It may be included in an amount of 27 parts by weight or less, 26 parts by weight or less, 25 parts by weight or less, 24 parts by weight or less, 23 parts by weight or less, 22 parts by weight or less, 21 parts by weight or less, 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, or 3 parts by weight or less.

[0023] A PBAT / lignin composite material according to one aspect of the present invention is biodegradable by any one of microorganisms, moisture, oxygen, light, and heat, and has excellent mechanical properties.

[0024] In one embodiment, the composite material may have a tensile strength of, for example, 10 to 40 MPa, 15 to 40 MPa, 20 to 35 MPa, 25 to 33 MPa, or 27 to 30 MPa.

[0025] In one embodiment, the tensile strain of the composite material may be, for example, 100 to 1200%, 500 to 1100%, or 900 to 1100%.

[0026] In one embodiment, the composite material may have a biodegradability of 90% or more in soil and ocean. Biodegradability is defined as the ratio of degradation compared to a standard material (e.g., cellulose) over the same period, and the Ministry of Environment of the Republic of Korea defines a material as biodegradable when its biodegradability is 90% or more compared to a standard material.

[0028] In another aspect, the present invention may relate to a biodegradable mulching film comprising the PBAT / lignin composite material.

[0029] In one embodiment, the physical properties of the mulching film may be in a range similar to or identical to the range of physical properties of the composite material.

[0030] In one embodiment, the mulching film exhibits a UV blocking effect by using the composite material and can improve lifespan characteristics by preventing easy aging from UV rays.

[0031] In one embodiment, the mulching film can exhibit excellent effects such as inhibiting moisture evaporation, inhibiting weed growth, inhibiting loss of fertilizer components in the soil, maintaining constant temperature and humidity, and heat retention.

[0033] In another aspect, the present invention may relate to a method for manufacturing a PBAT / lignin composite material.

[0034] In one embodiment, the manufacturing method may include mixing and compounding modified lignin, in which at least one terminal hydroxyl group is substituted with a phenolic group, and polybutylene adipate terephthalate (PBAT) at a temperature of 100 to 200°C.

[0035] In one embodiment, the mixing temperature may be 100°C or higher, 110°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, or 190°C or higher, and additionally, the mixing temperature may be 200°C or lower, 190°C or lower, 180°C or lower, 170°C or lower, 160°C or lower, 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower.

[0036] As the above-mentioned modified lignin and PBAT have been explained in detail above, further explanation is omitted.

[0038] As one embodiment, the present invention may provide the following embodiments.

[0039] A first embodiment comprises: a modified lignin in which at least one terminal hydroxyl group is substituted with a phenolic group; and

[0040] A PBAT / lignin composite material comprising polybutylene adipate terephthalate (PBAT) can be provided.

[0041] A second embodiment may provide a PBAT / lignin composite material, wherein, in the first embodiment, the modified lignin is represented by the following chemical formula 1:

[0042] [Chemical Formula 1]

[0043] .

[0044] A third embodiment can provide a PBAT / lignin composite material in which, in one or more of the first and second embodiments, the weight-average molecular weight (Mw) of the modified lignin is 500 or more and less than 5,000.

[0045] The fourth embodiment can provide a PBAT / lignin composite material in which, in one or more of the first to third embodiments, the number average molecular weight (Mn) of the modified lignin is 100 or more and less than 1,500.

[0046] The fifth embodiment can provide a PBAT / lignin composite material in which, in one or more of the first to fourth embodiments, the softening point of the modified lignin is 100 to 200°C.

[0047] The sixth embodiment may provide a PBAT / lignin composite material in which, in one or more of the first to fifth embodiments, the modified lignin is included in an amount of 1 to 30 parts by weight per 100 parts by weight of PBAT.

[0048] The seventh embodiment may provide a biodegradable mulching film comprising the PBAT / lignin composite material in one or more of the first to sixth embodiments.

[0049] The eighth embodiment may provide a method for manufacturing a PBAT / lignin composite material, comprising mixing and compounding modified lignin, in which at least one terminal hydroxyl group is substituted with a phenolic group, and polybutylene adipate terephthalate (PBAT) at a temperature of 100 to 200°C.

[0050] The ninth embodiment may provide a method for manufacturing a PBAT / lignin composite material, wherein, in the eighth embodiment, the modified lignin is represented by the following chemical formula 1:

[0051] [Chemical Formula 1]

[0052] .

[0053] The 10th embodiment can provide a method for manufacturing a PBAT / lignin composite material in which, in one or more of the 8th to 9th embodiments, the weight-average molecular weight (Mw) of the modified lignin is 500 or more and less than 5,000.

[0054] The 11th embodiment can provide a method for manufacturing a PBAT / lignin composite material in which, in one or more of the 8th to 10th embodiments, the number average molecular weight (Mn) of the modified lignin is 100 or more and less than 1,500.

[0055] The 12th embodiment can provide a method for manufacturing a PBAT / lignin composite material, wherein, in one or more of the 8th to 11th embodiments, the softening point of the modified lignin is 100 to 200°C.

[0056] The 13th embodiment may provide a method for manufacturing a PBAT / lignin composite material, wherein, in one or more of the 8th to 12th embodiments, the modified lignin and PBAT are mixed in a ratio of 1 to 30 parts by weight of the modified lignin to 100 parts by weight of the PBAT.

[0058] The contents of the present invention will be explained in more detail below through examples and test examples. However, these examples and test examples are provided merely to help understand the contents of the present invention, and the scope of the present invention is not limited to these examples and test examples. Modifications, substitutions, and insertions commonly known in the art may be performed, and such are also included within the scope of the present invention.

[0060] Examples and Test Examples

[0061] Preparation Example. Preparation of PBAT / lignin composite material

[0062] Modified lignin (PL) of Formula 1 above (weight-average molecular weight 2339, number-average molecular weight 764, Mw / Mn(PDI) 3.061, softening point 161.7°C) and Kraft lignin (KL) of Formula 2 below (weight-average molecular weight 5000~8000, number-average molecular weight 1500~2500, Mw / Mn(PDI) 3.0~4.5, softening point unmeasurable) were each mixed with PBAT of Formula 3 below, and specifically, mixed and compounded at 20 rpm for 30 minutes at 150°C using a kneader mixer (PBV-0.3, Irie Shokai Co.). At this time, PBAT / modified lignin composite materials (PBAT / PLx) were prepared by varying the content of modified lignin relative to the total weight of PBAT to 1 wt% (PBAT / PL1), 3 wt% (PBAT / PL3), 5 wt% (PBAT / PL5), 7 wt% (PBAT / PL7), 10 wt% (PBAT / PL10), 15 wt% (PBAT / PL15), and 20 wt% (PBAT / PL15), and PBAT / kraft lignin composite materials (PBAT / KLx) were prepared by varying the content of Kraft lignin relative to the total weight of PBAT to 1 wt% (PBAT / KL1), 3 wt% (PBAT / KL3), 5 wt% (PBAT / KL5), and 10 wt% (PBAT / KL10).

[0063] [Chemical Formula 2]

[0064]

[0065] [Chemical Formula 3]

[0066]

[0068] Test Example 1. Measurement of thermal decomposition degree

[0069] The degree of thermal decomposition (%) as a function of temperature was measured for the above PBAT / modified lignin composite material (PBAT / PLx) and PBAT / kraft lignin composite material (PBAT / KLx) using TGA (TGA55, TA Instruments Inc.). Specifically, the sample was placed in a platinum pan with a ceramic crucible pan and heated from 50°C to 800°C at a rate of 10°C / min under a nitrogen flow of 90 mL / min and a base flow of 10 mL / min to measure the degree of thermal decomposition (%). The results are shown in Figures 1a and 1b.

[0070] As shown in FIGS. 1a and 1b, it was confirmed that the residual amount of the composite material of PBAT and modified lignin increased as the content of modified lignin increased at 750°C. Specifically, at 750°C, the residual amount of PBAT itself was 3.7%, the residual amount of the composite material with a modified lignin content of 1 wt% was 3.85%, and the residual amount of the composite material with a modified lignin content of 20 wt% was 13.3%. On the other hand, it was confirmed that the composite material of PBAT and Kraft lignin showed a residual amount of 1% or less regardless of the lignin content. From this, it was found that the flame-retardant properties of the composite material of PBAT and modified lignin according to one embodiment of the present invention increase as the content of modified lignin increases, thereby increasing the residual amount.

[0072] Test Example 2. Measurement of mechanical properties

[0073] Mechanical properties (tensile strength, tensile strain, toughness) were measured for the above-mentioned PBAT / modified lignin composite (PBAT / PLx) and PBAT / kraft lignin composite (PBAT / KLx). Specifically, measurements were performed using a universal testing machine (UTM, Instron model 5567A, Instron Engineering Corporation, USA) equipped with a 2kN load cell. A dog bone-shaped tensile rod (approx. 10 mm (L) × 2 mm (W) × 1 mm (T), gauge length = 20 mm) was cut from the PBAT / lignin composite using a blade cutter. The measurements were taken with an initial grip width of 10 mm and a crosshead speed of 10 mm / min. Additionally, at least five different samples were measured for each composite, and the average values ​​were calculated. The results are shown in Table 1, Figures 2a, 2b, 3a, and 3b below.

[0074] Tensile strength (MPa) Tensile strain (%) Toughness (MJ / m 3 ) PBAT 28.45±0.20 907±28 174 PBAT / PL1 29.24±0.39 1050±26 218 PBAT / PL3 29.61±0.60 1050±25 220 PBAT / PL5 29.33±0.22 1000±4 207 PBAT / PL7 28.73±0.54 1020±25 211 PBAT / PL10 28.12±0.64 1040±49 208 PBAT / PL15 27.66±0.64 1050±53 193 PBAT / PL20 27.33±0.40 920±21 182 PBAT / KL1 26.77±0.18 855±14 159 PBAT / KL3 23.19±0.29 614±16 100 PBAT / KL5 22.94±0.91 609±60 89 PBAT / KL10 16.05±0.47 402±31 51

[0075] As shown in Table 1, Figures 2a, 2b, 3a, and 3b above, it was confirmed that in the case of the PBAT / Kraft Lignin composite material (PBAT / KLx), the tensile strength decreased by more than 20% when Kraft lignin was mixed at 3% by weight or more. On the other hand, in the case of the PBAT / modified lignin composite material (PBAT / PLx) according to one embodiment of the present invention, the tensile strength was 27 to 30 MPa, which was found to be similar to that of PBAT (approx. 28.45 MPa). In addition, while PBAT has a high tensile strain and stretches up to approximately 900%, in the case of the PBAT / Kraft Lignin composite material (PBAT / KLx), it was confirmed that the tensile strain also decreased significantly along with the decrease in tensile strength. On the other hand, in the case of the PBAT / modified lignin composite material (PBAT / PLx) according to one embodiment of the present invention, it was confirmed that the tensile strain is very high and can be stretched up to 1050%.

[0076] From the above results, it was confirmed that the PBAT / modified lignin composite material (PBAT / PLx) according to one embodiment of the present invention maintains the biodegradability of PBAT while also exhibiting excellent mechanical properties.

[0078] Test Example 3. Measurement of UV blocking power

[0079] UV blocking properties were evaluated for the above PBAT / modified lignin composite (PBAT / PLx) and PBAT / kraft lignin composite (PBAT / KLx) using UV-vis light transmittance analysis. Specifically, UV / Vis transmittance was measured using UV-Vis spectroscopy (UV-Vis JASCO V-670 spectrometer) in the wavelength range of 200 to 700 nm. The results are shown in Figure 4.

[0080] As shown in Figure 4, it was confirmed that all composite materials with added lignin exhibited a transmittance close to zero in the ultraviolet region below 400 nm, which was attributed to the increased UV blocking effect due to the benzene structure of lignin. Furthermore, it was confirmed that the composite materials exhibited lower transmittance when modified lignin was added compared to when Kraft lignin was added, and that they possessed superior light blocking characteristics as the transmittance decreased not only in the ultraviolet region but also in the visible light region.

Claims

Claim 1 Modified lignin having at least one terminal hydroxyl group substituted with a phenolic group; and polybutylene adipate terephthalate (PBAT), wherein the modified lignin is represented by the following Chemical Formula 1: [Chemical Formula 1] , the above modified lignin is a PBAT / lignin composite material having one or more of the following characteristics: (a) a weight-average molecular weight (Mw) of 500 or more and less than 5,000; (b) a number-average molecular weight (Mn) of 100 or more and less than 1,500; and (c) a softening point of 100 to 200℃. Claim 2 A PBAT / lignin composite material according to claim 1, wherein the modified lignin is included in an amount of 1 to 30 parts by weight per 100 parts by weight of PBAT. Claim 3 A biodegradable mulching film comprising a PBAT / lignin composite material according to claim 1 or 2. Claim 4 A method for manufacturing a PBAT / lignin composite material comprising mixing and compounding modified lignin, in which at least one terminal hydroxyl group is substituted with a phenolic group, and polybutylene adipate terephthalate (PBAT) at a temperature of 100 to 200°C, wherein the modified lignin is represented by the following Chemical Formula 1: [Chemical Formula 1] A method for manufacturing a PBAT / lignin composite material, wherein the modified lignin has one or more of the following characteristics: (a) a weight-average molecular weight (Mw) of 500 or more and less than 5,000; (b) a number-average molecular weight (Mn) of 100 or more and less than 1,500; and (c) a softening point of 100 to 200℃. Claim 5 A method for manufacturing a PBAT / lignin composite material according to claim 4, wherein the modified lignin and PBAT are mixed in a ratio of 1 to 30 parts by weight of the modified lignin to 100 parts by weight of the PBAT. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete

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