A super-tough PLA / SiR blend and its preparation method

Abstract

The present invention belongs to the technical field of polymer materials, and particularly relates to a super-tough PLA / SiR blend and a preparation method thereof. Using polylactic acid, silicone rubber, and glycidyl methacrylate-grafted silicone rubber (SiR-g-GMA) as raw materials, a super-tough and low-temperature impact-resistant PLA / SiR blend is prepared. The SiR-g-GMA copolymer, as a reactive compatibilizer, can undergo grafting reactions with the terminal hydroxyl and carboxyl groups in the PLA molecular chain, improving the interfacial interaction force between the PLA and SiR phases. The PLA / SiR blend has excellent low-temperature impact resistance, and the impact strength can reach 75 kJ / m 2 at -20 °C, greatly expanding the application range of the PLA / SiR blend. The process of the present invention is simple, the equipment is ordinary, and it is easy to realize industrial production, and the raw materials used are widely sourced.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a super-tough PLA / SiR blend and a preparation method thereof. Background Art

[0002] Polylactic acid (PLA) is an aliphatic polyester obtained by extracting and fermenting lactic acid monomers from crop fruits or crop straws and then chemically synthesizing them. It has good biocompatibility, can be completely degraded in nature, and the final degradation products are water and carbon dioxide, without causing environmental pollution. At the same time, it has a relatively high tensile strength (>60 MPa), is easy to process and form, and is inexpensive. However, the toughness of polylactic acid is poor and it is easy to break, which greatly limits the application range of polylactic acid.

[0003] SiR is a polysiloxane composed of a silicon-oxygen bond skeleton. It is the most numerous, deeply studied, and widely used class of organosilicon compounds. Silicone rubber has high thermal stability, excellent low-temperature performance, and excellent electrical insulation, weather resistance, ozone resistance, and air permeability, and is non-toxic and odorless.

[0004] Therefore, blending PLA and SiR to prepare a super-tough material can complement the advantages and disadvantages of the two materials. However, the compatibility of the polylactic acid and silicone rubber blend prepared by simple blending is poor, and the improvement of its toughness is very limited. Summary of the Invention

[0005] The purpose of the present invention is to develop a super-tough PLA / SiR blend and a preparation method thereof.

[0006] The raw materials and mass ratios of the super-tough PLA / SiR blend are as follows:

[0007] The mass fraction of PLA: 100 parts, the mass fraction of SiR masterbatch: 10 - 25 parts, the mass fraction of SiR-g-GMA copolymer: 5 - 15 parts, and the vulcanizing agent: 0.1 - 1.0 part.

[0008] Among them, the preparation method of SiR-g-GMA is as follows:

[0009] Accurately weigh 100 parts of silicone rubber and 5 - 20 parts of glycidyl methacrylate (GMA) and pre-mix them. At a temperature of 160 - 185 °C and a rotation speed of 30 - 50 rpm, after blending for 3 minutes, add 0.1 - 1.0 part of DCP vulcanizing agent for grafting reaction and knead for 12 minutes, then collect the product to obtain the graft product SiR-g-GMA of silicone rubber and GMA.

[0010] The preparation method of SiR masterbatch is as follows:

[0011] First, turn on the internal mixer. The temperature is 70°C and the rotational speed is 30 - 50 rpm. Weigh accurately 100 parts of silicone rubber (SiR), 10 - 50 parts of fumed silica, and 1 - 5 parts of hydroxyl silicone oil. Add fumed silica and hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the internal mixer reaches 180°C, first add silicone rubber (SiR), and then pour the evenly mixed material in portions. After kneading for 8 - 30 minutes, collect the product.

[0012] The present invention also provides a method for preparing a PLA / SiR blend:

[0013] Dry PLA in a vacuum drying oven at 70°C for 2 hours. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer into the internal mixer according to the proportion, and melt and mix them in the internal mixer for 3 - 5 minutes. Then add the vulcanizing agent bis(2,5-dimethyl-2,5-di(tert-butylperoxy)hexane) (DBPMH) and react for 5 - 8 minutes. The heating temperature of the internal mixer is 180 - 195°C, and the rotor speed is 30 - 50 rpm to obtain the PLA / SiR blend.

[0014] Prepare SiR-g-GMA and SiR masterbatch polymers by the method of the present invention and add them into the PLA blend system. The addition amounts of SiR-g-GMA and SiR masterbatch in the blend system are 15 - 40 parts.

[0015] Advantages of the present invention:

[0016] 1. In the present invention, the PLA, SiR-g-GMA, and SiR masterbatch copolymers are melt-blended. The SiR-g-GMA polymer is added to the PLA / SiR blend to improve the compatibility between PLA and SiR. During melt-blending, the epoxy groups in GMA can react with the terminal hydroxyl and carboxyl groups in the PLA molecular chain and the methyl groups in the silicone rubber, improving the interfacial interaction force between the two phases of PLA and SiR, and significantly improving the mechanical properties of the polymer. The prepared PLA / SiR blend has both the high strength of PLA and the good toughness and ductility of SiR.

[0017] 2. Both PLA and SiR are environmentally friendly materials. PLA has excellent biocompatibility and biodegradability. Therefore, the PLA / SiR blend has great application potential in the field of disposable packaging. Description of the Drawings

[0018] Figure 1 It is the electron micrograph of the quenched cross-section of the blends of Example 16(a) and Comparative Example 1(b). Detailed Embodiments

[0019] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Example 1

[0021] Weigh 100 parts of silicone rubber and 5 parts of GMA and pre-mix them. Pour the mixture into a mixer. The mixing temperature is 160 °C, the rotation speed is 30 rpm. After mixing for 3 minutes, add 0.1 part of DCP for grafting reaction. After reacting for 12 minutes, collect the product to obtain the grafted product SiR-g-GMA of silicone rubber and GMA.

[0022] Example 2

[0023] Weigh 100 parts of silicone rubber and 10 parts of GMA and pre-mix them. Pour the mixture into a mixer. The mixing temperature is 170 °C, the rotation speed is 40 rpm. After mixing for 3 minutes, add 0.5 part of DCP for grafting reaction. After reacting for 12 minutes, collect the product to obtain the grafted product SiR-g-GMA of silicone rubber and GMA.

[0024] Example 3

[0025] Weigh 100 parts of silicone rubber and 20 parts of GMA and pre-mix them. Pour the mixture into a mixer. The mixing temperature is 185 °C, the rotation speed is 50 rpm. After mixing for 3 minutes, add 1 part of DCP for grafting reaction. After reacting for 12 minutes, collect the product to obtain the grafted product SiR-g-GMA of silicone rubber and GMA.

[0026] Example 4

[0027] First, turn on the mixer, with a temperature of 70 °C and a rotation speed of 30 rpm. Accurately weigh 100 parts of SiR and 10 parts of fumed silica. Add fumed silica and 1 part of hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the mixer reaches 180 °C, first add SiR, and then evenly add the mixed material in portions. After mixing for 8 minutes, collect the product.

[0028] Example 5

[0029] First, turn on the internal mixer with a temperature of 70 °C and a rotational speed of 30 rpm. Weigh accurately 100 parts of SiR and 20 parts of fumed silica. Add fumed silica and 2 parts of hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the internal mixer reaches 180 °C, first add SiR, then pour the mixture evenly in portions, and collect the product after mixing for 13 minutes.

[0030] Example 6

[0031] First, turn on the internal mixer with a temperature of 70 °C and a rotational speed of 40 rpm. Weigh accurately 100 parts of SiR and 30 parts of fumed silica. Add fumed silica and 3 parts of hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the internal mixer reaches 180 °C, first add SiR, then pour the mixture evenly in portions, and collect the product after mixing for 18 minutes.

[0032] Example 7

[0033] First, turn on the internal mixer with a temperature of 70 °C and a rotational speed of 50 rpm. Weigh accurately 100 parts of SiR and 40 parts of fumed silica. Add fumed silica and 4 parts of hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the internal mixer reaches 180 °C, first add SiR, then pour the mixture evenly in portions, and collect the product after mixing for 23 minutes.

[0034] Example 8

[0035] First, turn on the internal mixer with a temperature of 70 °C and a rotational speed of 50 rpm. Weigh accurately 100 parts of SiR and 50 parts of fumed silica. Add fumed silica and 5 parts of hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the internal mixer reaches 180 °C, first add SiR, then pour the mixture evenly in portions, and collect the product after mixing for 30 minutes.

[0036] Example 9

[0037] Tough PLA / SiR blend, the raw materials and their component ratios are as follows:

[0038] Mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 5 parts (Example 1), mass fraction of SiR masterbatch: 10 parts (Example 4), vulcanizing agent: 0.8 part.

[0039] The preparation process of the tough PLA / SiR blend is as follows:

[0040] The PLA was dried in a vacuum drying oven at 70 °C for 2 h. The dried PLA, SiR masterbatch, and SiR-g-GMA polymer were added to a kneader and melt-mixed in the kneader for 3 min, and then 0.8 parts of DBPMH was added and reacted for 5 min. The heating temperature of the kneader was 180 °C, and the rotor speed was 30 rpm to obtain a PLA / SiR blend.

[0041] Example 10

[0042] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 5 parts (Example 1), mass fraction of SiR masterbatch: 10 parts (Example 5), 0.3 parts of vulcanizing agent.

[0043] Super-tough PLA / SiR blend, the preparation process is as follows:

[0044] The PLA was dried in a vacuum drying oven at 70 °C for 2 h. The dried PLA, SiR masterbatch, and SiR-g-GMA polymer were added to a kneader and melt-mixed in the kneader for 4 min, and then 0.3 parts of DBPMH was added and reacted for 8 min. The heating temperature of the kneader was 185 °C, and the rotor speed was 40 rpm to obtain a PLA / SiR blend.

[0045] Example 11

[0046] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 15 parts (Example 1), mass fraction of SiR masterbatch: 10 parts (Example 6), 0.5 parts of vulcanizing agent.

[0047] Super-tough PLA / SiR blend, the preparation process is as follows:

[0048] The PLA was dried in a vacuum drying oven at 70 °C for 2 h. The dried PLA, SiR masterbatch, and SiR-g-GMA polymer were added to a kneader and melt-mixed in the kneader for 6 min, and then 0.5 parts of DBPMH was added and reacted for 7 min. The heating temperature of the kneader was 190 °C, and the rotor speed was 50 rpm to obtain a PLA / SiR blend.

[0049] Example 12

[0050] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows:

[0051] Mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 10 parts (Example 2), mass fraction of SiR masterbatch: 10 parts (Example 6), vulcanizing agent: 0.5 part.

[0052] Super-tough PLA / SiR blend, the preparation process is as follows:

[0053] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer into a mixer, melt and mix in the mixer for 3 min, then add 0.5 part of DBPMH and react for 6 min. The heating temperature of the mixer is 190 °C, and the rotor speed is 40 rpm to obtain the PLA / SiR blend.

[0054] Example 13

[0055] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows:

[0056] Mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 5 parts (Example 2), mass fraction of SiR masterbatch: 10 parts (Example 7), vulcanizing agent: 0.8 part.

[0057] Super-tough PLA / SiR blend, the preparation process is as follows:

[0058] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer into a mixer, melt and mix in the mixer for 5 min, then add 0.8 part of DBPMH and react for 8 min. The heating temperature of the mixer is 185 °C, and the rotor speed is 40 rpm to obtain the PLA / SiR blend.

[0059] Example 14

[0060] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows: Mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 10 parts (Example 2), mass fraction of SiR masterbatch: 10 parts (Example 8), vulcanizing agent: 1 part.

[0061] Super-tough PLA / SiR blend, the preparation process is as follows:

[0062] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer into a mixer, melt and mix in the mixer for 3 min, then add 1 part of DBPMH and react for 5 min. The heating temperature of the mixer is 185 °C, and the rotor speed is 40 rpm to obtain the PLA / SiR blend.

[0063] Example 15

[0064] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 15 parts (Example 3), mass fraction of SiR masterbatch: 10 parts (Example 8), vulcanizing agent: 0.3 part.

[0065] Super-tough PLA / SiR blend, the preparation process is as follows:

[0066] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer into a mixer, melt and mix them in the mixer for 4 min, then add 0.3 part of DBPMH and react for 6 min. The heating temperature of the mixer is 185 °C, and the rotor speed is 40 rpm to obtain the PLA / SiR blend.

[0067] Example 16

[0068] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 10 parts (Example 3), mass fraction of SiR masterbatch: 20 parts (Example 7), vulcanizing agent: 0.3 part.

[0069] Super-tough PLA / SiR blend, the preparation process is as follows:

[0070] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer into a mixer, melt and mix them in the mixer for 5 min, then add 0.3 part of DBPMH and react for 6 min. The heating temperature of the mixer is 185 °C, and the rotor speed is 50 rpm to obtain the PLA / SiR blend.

[0071] The quenched cross-section morphology of Example 16 is as Figure 1 shown. Compared with the comparative example without adding SiR-g-GMA and silica, in the compatibilized PLA / SiR blend, the phase interface between PLA and SiR is blurred, the SiR phase domain size is significantly reduced, and the compatibility is significantly improved.

[0072] Example 17

[0073] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows:

[0074] Mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 15 parts (Example 1), mass fraction of SiR masterbatch: 20 parts (Example 6), vulcanizing agent: 1 part.

[0075] Super-tough PLA / SiR blend, the preparation process is as follows:

[0076] The PLA was dried in a vacuum drying oven at 70 °C for 2 h. The dried PLA, SiR masterbatch, and SiR-g-GMA polymer were added to a mixer and melt-mixed in the mixer for 4 min, then 1 part of DBPMH was added and reacted for 6 min. The heating temperature of the mixer was 190 °C and the rotor speed was 40 rpm to obtain a PLA / SiR blend.

[0077] Example 18

[0078] Tough PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 5 parts (Example 2), mass fraction of SiR masterbatch: 25 parts (Example 7), 0.3 parts of vulcanizing agent.

[0079] Tough PLA / SiR blend, the preparation process is as follows:

[0080] The PLA was dried in a vacuum drying oven at 70 °C for 2 h. The dried PLA, SiR masterbatch, and SiR-g-GMA polymer were added to a mixer and melt-mixed in the mixer for 4 min, then 0.3 part of DBPMH was added and reacted for 6 min. The heating temperature of the mixer was 195 °C and the rotor speed was 40 rpm to obtain a PLA / SiR blend.

[0081] Example 19

[0082] Tough PLA / SiR blend, the raw materials and their component ratios are as follows:

[0083] Mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 15 parts (Example 2), mass fraction of SiR masterbatch: 25 parts (Example 8), 0.3 parts of vulcanizing agent.

[0084] Tough PLA / SiR blend, the preparation process is as follows:

[0085] The PLA was dried in a vacuum drying oven at 70 °C for 2 h. The dried PLA, SiR masterbatch, and SiR-g-GMA polymer were added to a mixer and melt-mixed in the mixer for 4 min, then 0.3 part of DBPMH was added and reacted for 6 min. The heating temperature of the mixer was 185 °C and the rotor speed was 40 rpm to obtain a PLA / SiR blend.

[0086] Example 20

[0087] Super-tough PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR-g-GMA: 15 parts (Example 3), mass fraction of SiR masterbatch: 25 parts (Example 8), vulcanizing agent: 0.3 part.

[0088] Super-tough PLA / SiR blend, the preparation process is as follows:

[0089] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, SiR masterbatch, and SiR-g-GMA polymer to a mixer, melt and mix them in the mixer for 4 min, then add 0.3 part of DBPMH and react for 5 min. The heating temperature of the mixer is 190 °C, and the rotor speed is 50 rpm to obtain the PLA / SiR blend.

[0090] Comparative Example 1

[0091] PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of SiR: 20 parts (raw rubber without pretreatment), vulcanizing agent: 0.3 part.

[0092] PLA / SiR blend, the preparation process is as follows:

[0093] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA and SiR to a mixer, melt and mix them in the mixer for 4 min, then add 0.3 part of DBPMH and react for 5 min. The heating temperature of the mixer is 190 °C, and the rotor speed is 50 rpm to obtain the PLA / SiR blend.

[0094] Comparative Example 2

[0095] PLA / SiR blend, the raw materials and their component ratios are as follows: mass fraction of PLA: 100 parts, mass fraction of castor oil (COP): 10 parts, mass fraction of SiR coagulum: 20 parts (Example 7), vulcanizing agent: 0.3 part.

[0096] PLA / SiR / COP blend, the preparation process is as follows:

[0097] Dry PLA in a vacuum drying oven at 70 °C for 2 h. Add the dried PLA, COP, and SiR coagulum to a mixer, melt and mix them in the mixer for 4 min, then add 0.3 part of DBPMH and react for 5 min. The heating temperature of the mixer is 190 °C, and the rotor speed is 50 rpm to obtain the PLA / SiR / COP blend.

[0098] Table 1

[0099]

[0100] As described above, it is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A super-tough PLA / SiR blend, characterized in that, The composition of the blend by mass parts is as follows: PLA: 100 parts, SiR masterbatch: 10 - 25 parts, SiR- g -GMA copolymer: 5 - 15 parts, vulcanizing agent: 0.1 - 1.0 part; The preparation method of the SiR- g -GMA is as follows: accurately weigh silicone rubber SiR and glycidyl methacrylate GMA and pre-mix them. After 3 minutes of blending, add a vulcanizing agent and carry out a grafting reaction for 12 minutes, then collect the product to obtain the graft product SiR- g -GMA; Preparation of SiR- g -GMA consists of the following raw materials in parts by mass: 100 parts of silicone rubber, 5-20 parts of GMA, and 0.1-1.0 part of vulcanizing agent; The preparation method of the SiR compound is as follows: Turn on the internal mixer, with a temperature of 70 °C and a rotational speed of 30 - 50 rpm. Accurately weigh silicone rubber SiR, fumed silica, and hydroxyl silicone oil. Add fumed silica and hydroxyl silicone oil into a beaker in sequence. The mass fraction of hydroxyl silicone oil is 10% of that of fumed silica. Mix fumed silica and hydroxyl silicone oil evenly in a high-speed mixer. After the temperature of the internal mixer reaches 180 °C, first add silicone rubber SiR, and then pour the mixture evenly in portions. After mixing for 8 - 30 minutes, collect the product. The raw materials for preparing the SiR compound are composed in parts by mass as follows: 100 parts of silicone rubber SiR, 10 - 50 parts of fumed silica, and 1 - 5 parts of hydroxyl silicone oil.

2. The super-tough PLA / SiR blend according to claim 1, characterized in that: The vulcanizing agent is dicumyl peroxide (DCP); the blending temperature is 160 - 185 °C, and the rotational speed is 30 - 50 rpm.

3. A method for preparing the super-tough PLA / SiR blend according to claim 1, characterized in that: The preparation method of the PLA / SiR blend is as follows: Dry PLA in a vacuum drying oven at 70 °C for 2 h, and then add the dried PLA, SiR masterbatch, and SiR- g -GMA polymer into a mixer. Melt and mix them in the mixer for 3 - 5 min, and then add a vulcanizing agent and react for 5 - 8 min to obtain the PLA / SiR blend.

4. The preparation method of the super-tough PLA / SiR blend according to claim 3, characterized in that: The vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and its dosage is 0.1 - 1.0 part; the heating temperature of the internal mixer is 180 - 195 °C, and the rotor speed is 30 - 50 rpm.

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