Polylactic acid block copolymer

A technology of block copolymer and polylactic acid, which is applied in the field of polylactic acid block copolymer, can solve the problems of difficult preparation of polylactic acid block copolymer, long reaction time, irregular arrangement of chain segments, etc.

Active Publication Date: 2012-12-19
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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Problems solved by technology

However, since the melt polycondensation needs to be carried out under high temperature and high vacuum conditions, the reaction time is long, and the transesterification reaction is prone to occur. The arrangement of the segments in the obtained copolymer is irregular. At the same time, the lactic acid often undergoes a racemization reaction. It exists in an amorphous state, and the content of polylactic acid can only reach 30% at most, which directly affects the biodegradable characteristics of the material (Licheng Tan et al., J Therm Anal Calorim, 2010 99:269-275; Journal of Applied Polymer Science , 2008 108:2171-2179)
Chinese patent CN101338025A first introduces long-chain aliphatic dihydric alcohols into the PET chain to obtain a modified PET with a low melting point, and then uses isocyanate to couple the modified PET and The method of hydroxyl-terminated polylactic acid oligomers has produced a series of multi-block copolymers containing polylactic acid segments, but because it is carried out under the conditions of melt coupling, some mixtures are obtained, which are difficult to separate and cannot Obtained block copolymers with well-defined structures
If melt polymerization is used, polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT) and polybutylene terephthalate with a melting point higher than 220°C are used (PBT) These initiators, to initiate the ring-opening polymerization of lactide, in addition to serious transesterification reactions, will inevitably bring about the racemization and degradation of the raw material lactide and the reaction product polylactic acid. It is difficult to prepare polylactic acid block copolymers containing high melting point polyesters such as PET, PTT, and PBT by the method of ring polymerization

Method used

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  • Polylactic acid block copolymer

Examples

Experimental program
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Effect test

Embodiment 1

[0040] Synthesis of block copolymers of polybutylene terephthalate (PBT) and polylactic acid (PLA).

[0041] Step (1). Ethanol triggers ring-opening polymerization of cyclic polybutylene terephthalate (CBT) to obtain single-end hydroxyl polybutylene terephthalate

[0042] Under nitrogen protection, 10gCBT, 0.5g ethanol and 0.105g Sn(Oct) 2 Put into the reaction bottle of 100ml that has been roasted over fire and has been cooled with nitrogen protection. Add 5ml of o-dichlorobenzene treated with anhydrous and anaerobic by syringe, so that the concentration of CBT is 2Kg / L, and the concentration of ethanol is 100g / L. The reaction was carried out at 180°C. After 10 minutes, the reaction was over (GPC monitoring showed no signal peak of CBT), cooled and filtered, and the reaction product was washed with anhydrous chloroform to wash away traces of unreacted CBT monomer. Vacuum at 80°C drying.

[0043] Step (2). Single-terminal hydroxyl PBT initiates lactide polymerization. The ...

Embodiment 2

[0053] Synthesis of block copolymers of polytrimethylene terephthalate (PTT) and polylactic acid (PLA).

[0054] Step (1). Methanol initiates ring-opening polymerization of cyclic polytrimethylene terephthalate (CTT) to obtain single-end hydroxyl polytrimethylene terephthalate

[0055] Under nitrogen protection, 10g CTT, 1.0g methanol and 0.0011g SnCl 2 Put into the reaction bottle of 100ml that has been roasted over fire and has been cooled with nitrogen protection. Add 5ml of tetrachloroethane treated with anhydrous and anaerobic by syringe, so that the concentration of CTT is 2Kg / L, and the concentration of methanol is 200g / L. The reaction was carried out at 180°C. After 5 minutes, the reaction was over (GPC monitoring showed no signal peak of CTT), cooled and filtered, and the reaction product was washed with anhydrous chloroform to wash away traces of unreacted CTT monomer. Vacuum at 60°C drying.

[0056] Step (2). Single-terminal hydroxyl PTT initiates lactide polymer...

Embodiment 3

[0066] Synthesis of block copolymers of polyethylene terephthalate (PET) and polylactic acid (PLA).

[0067] Step (1). 1-propanol initiates ring-opening polymerization of cyclic polyethylene terephthalate (CET) to obtain single-end hydroxyl polyethylene terephthalate

[0068] Under nitrogen protection, 10 g CET, 0.1 g 1-propanol and 0.0101 g SnBr 2 Put into the reaction bottle of 100ml that has been roasted over fire and has been cooled with nitrogen protection. Add 50ml of anhydrous and anaerobic treated nitrobenzene with a syringe, so that the concentration of CET is 0.2Kg / L, and the concentration of 1-propanol is 2g / L. The reaction was carried out at 120°C. After 60 minutes, the reaction was over (GPC monitoring had no signal peak of CET), cooled and filtered, and the reaction product was washed with anhydrous chloroform to wash away traces of unreacted CET monomers, and vacuumed at 80°C. drying.

[0069] Step (2). Single-end hydroxyl PET initiates lactide polymerization...

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Abstract

The invention relates to a polylactic acid block copolymer, which solves the problems that current method is hard to prepare the polylactic acid block copolymer with high-melting point polyester. The polylactic acid block copolymer is a two-block copolymer which is shown as A-b-B, wherein A is a single-end hydroxyl aromatic polyester block, and B is a polylactic acid block. The polylactic acid block is one or more of a poly-L-lactic acid block, a poly-D-lactic acid block and a poly-DL lactic acid block. The polylactic acid block copolymer is prepared by the following step of: adopting an organic solvent which can dissolve reactants of single-end hydroxyl aromatic polyester and lactide to be a reaction medium, tin salt as a catalyst, and the single-end hydroxyl aromatic polyester as an initiator to initiate the ring opening polymerization of lactide. With the adoption of the polylactic acid block copolymer, the polymerizing temperature can be controlled to reach a scope in which polylactic acid and lactide cannot be degraded, and the racemization cannot be carried out, so that the generation of transesterification can be effectively inhibited, the regularity of the chain section can be ensured, and the block copolymers of polyester and the polylactic acid can be successfully prepared, including aromatic polyester with the high-melting point.

Description

[0001] This application is a divisional application of a patent application with an application date of May 12, 2011, an application number of 201110122512.1, and an invention title of "A Polylactic Acid Block Copolymer and Its Preparation Method". technical field [0002] The invention belongs to the technical field of polymer materials, and relates to a polylactic acid block copolymer. technical background [0003] Polylactic acid (PLA) has attracted widespread attention because of its raw material lactic acid's biomass source and biodegradability, and has similar processing performance and mechanical physical properties to general plastics such as polypropylene and polyethylene. It has a wide range of uses and huge market potential, but compared with aromatic polyesters such as polyethylene terephthalate (PET), polylactic acid is obviously brittle and has poor impact resistance, which to a certain extent This limits its wider application. [0004] It is hoped to impr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/60
Inventor 周坚陈鹏顾群黎俊施文涛史佳鑫王宗宝蒋志强
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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