Study On The Synthesis And Properties Of PA6-co-PCL Random Copolymer

Polyamide(PA),commonly known as nylon,has many excellent properties such as high mechanical strength,good thermal performance,easy processing and so on.However,due to the existence of a large number of strong polar amide groups,PA is easy to absorb water.Polycaprolactone(PCL)is a hydrophobic aliphatic polyester with good biocompatibility,degradability and crystallinity,but its mechanical strength is low.Therefore,it is urgent to reduce the water absorption and melting point and improve the processability of PCL.The main work of this paper is to introduce hydrophobic and biodegradable PCL into PA6 molecular chain.Through the co-regulation of chemical structure and physical structure,the effects of the two on the crystallinity,degradation and water absorption properties of each other are studied.At the same time,the copolymer is used as compatibilizer of PA6 and PCL blends,and its application in blending modification of PA6 and PCL is explored.The main contents are as follows:A series of P(CLA-co-CLO)polyesteramide samples with different compositions were synthesized by anionic ring-opening polymerization,and the structure and composition of the copolymers were characterized by 1H NMR,13C NMR and FTIR.The results showed that the structure and composition of the copolymers were controllable.Through the TGA results,it can be found that the introduction of PCLA segments can significantly improve the thermal stability of PCLO segments.The results show that the introduction of PCLO segments reduces the melting temperature of PCLA segments and increases the isothermal crystallization rate of PCLA segments.In addition,when the design content of PCLO is 25%-50%,both PCLA and PCLO segments can crystallize,and the crystalline morphology and spherulite growth rate of PCLO are affected by the physical structure of PCLA.The water absorption experiments show that the water absorption of the copolymer decreases significantly with the increase of PCLO content.On the one hand,hydrophobic PCLO itself can reduce the water absorption of the material.On the other hand,the introduction of PCLO can also affect the water absorption of the material by regulating the physical structure.The results showed that the introduction of PCLO gave the copolymer a certain degree of degradability.The results of compatibility of PCL/PA6 blends show that PCL and PA6 are incompatible polymers.The addition of copolymer significantly improves the compatibility of two phases and promotes the formation of bicontinuous phase.The formation of this structure is expected to greatly improve the comprehensive properties of the blends.In addition,it was found that the copolymer could improve the compatibility of incompatible blend PA6/PCL.The results of this work provide basic data for the copolymerization modification of PCL and PA6,and hopefully make a breakthrough in the application of blending modification of polyester and polyamide 6.