Completely biodegradable aliphatic copolyester containing annular sugar alcohol structure and preparation method of completely biodegradable aliphatic copolyester

Abstract

The invention discloses completely biodegradable aliphatic copolyester containing an annular sugar alcohol structure. The completely biodegradable aliphatic copolyester is prepared by introducing structural units shown by III on the basis of polyester structural units shown by I and II and carrying out copolymerization on the structural units, wherein the amount of the structural units of I is as follows: the amount of the structural units of II and III is equal to 1, the amount of the structural units of III accounts 1-40 percent for that of I, number average molecular weight of the copolyester is 16000-83000g / mol, glass transition temperature ranges from 57 DEG C below zero to 4 DEG C, tensile strength of an acquired film is 8-49 MPa, and elongation at break is 280-950 percent. The invention also discloses a preparation method of the completely biodegradable aliphatic copolyester. With the adoption of the preparation method, as rigid annular sugar alcohol comonomer without toxin and with good thermal stability and hydrophilicity is introduced and the dosage of the rigid annular sugar alcohol comonomer is low, influence forced on polymerization rate is limited, so that molecular weight of the acquired copolyester is enough high, the copolyester is also endowed with excellent thermal stability, degradation property and hydrophilicity, and the elongation at break is greatly increased; in addition, the preparation method is simple to operate, is mature in process, is easy to control and is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of fully biodegradable aliphatic copolyester and its preparation, in particular to a fully biodegradable aliphatic copolyester based on renewable biomass and its preparation method, in particular to A completely biodegradable aliphatic copolyester with a sugar alcohol structure and a preparation method thereof, the copolyester has excellent thermal properties, degradation properties and mechanical properties. Background technique [0002] Polymer material is one of the three basic materials juxtaposed with inorganic non-metallic materials and metal materials. As a material with the widest application, the largest output and the most varieties in the world today, it has made great contributions to the development of human society. However, it also faces great challenges: on the one hand, traditional polymer materials are difficult to degrade after being discarded, and a large number of applications will undou...

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Problems solved by technology

The above research shows that the introduction of rigid structural units can obtain aliphatic copolyesters with better performance, but the problem of traditional copolymerization modification is that the aromatic benzene ring or alicyclic structure used comes from limited petrochemical resources, which is not conducive to its sustainable development. development; this type of structure is basically not biodegradable, not only the biodegradability of the copolyester decreases with the increase of its content, but also its glass transition temperature is also lower, etc.

[0005] Dianhydrohexitol is a typical bio-based monomer with a ring-shaped rigid structure, which can be decomposed into polysaccharides from starch in cereals by enzymatic catalysis, and then hydrogenated and dehydrated. It has the advantages of toxicity and good thermal stability. It has three isomers, namely isosorbide, isomannide and isoidide. Since dianhydrohexitol is a secondary alcohol, the reactivity is low.

In order to improve the molecular weight of polyester obtained from dianhydrohexitol and aliphatic dibasic acid, many scholars such as Braun et al. A method of activating carboxylic acid into dichloride of dicarboxylic acid, and then carrying out solution condensation reaction with dianhydrohexitol, although the number-average molecular weight of polyester obtained by this method can be increased to 6000-23000g / mol, but the On the one hand, because the monomer needs to be activated first, the chloride used has great toxic and side effects, which is neither economical nor environmentally friendly. On the other hand, because the solution polymerization method is used, the operation is complicated and it is not suitable for large-scale industrial production.

In addition, the above research did not give a specific description of the preparation, glass transition temperature, mechanical properties, hydrophilicity, etc. of high molecular weight aliphatic copolyesters based on low-content dianhydrohexitol.

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