Study On Preparation Of Carbon Material/copolyamide 6/11 Composite By In-situ Polymerization

Polyamide has good processing properties and performance,and is almost the top five general engineering plastics.As a polymer material,the insulating properties and water absorption of the polyamide itself limit its application.In this paper,caprolactam,11-aminoundecanoic acid and carbon materials(graphene and carbon nanotubes)were used as raw materials to prepare high performance PA 6/11 composites by batch high pressure polymerization and in situ melt polycondensation.The effects of reactor volume and carbon material addition on PA 6/11 synthesis process and composite materials were systematically studied.The LCA method was used to evaluate the environmental impact during the synthesis process.The main research contents are as follows:The polymerization process of PA 6/11 was studied in 1L,5L and 10 L reactors.The difference in the polymerization process of different volume reactors was mainly reflected in the smaller the reactor volume,the shorter the polycondensation time required for the polymerization system,and the final polymerization.The relative viscosity of PA 6/11 is larger,the melting point is higher,and the thermal stability of PA 6/11 synthesized by different reactors is not much different.The relative viscosity of the PA 6/11 slice obtained by polymerization in a 10 L reactor was 2.80.PA 6/11 composites with different contents of CNTs and GR were added.The relative viscosities of the slices were around 2.75 and 2.73,respectively.With the increase of the content of CNTs and GR,the proportion of oligomer components is increasing.With the increasing content of CNTs,the thermal stability of the composites also increased first and then decreased.In the PA 6/11 polymer system,the addition of GR and the addition of GR increased the stability of the composites with the increase of GR content and then decreased first and then increased.The injection molding temperature of PA 6/11 composites containing CNTs is 240~250°C,the injection pressure is 50~60MPa,the temperature of injection molding die is about 25°C;the injection molding temperature of PA 6/11 composites of GR is 235~250?,the injection pressure is 50-60 MPa,and the temperature of the injection molding die is about 75°C.The introduction of carbon materials significantly improved the mechanical and electrical properties of PA 6/11 composites.For PA 6/11 composite systems with carbon materials,the addition of carbon materials ranged from 0.10 to 0.50 wt.%.The composite materials have excellent mechanical properties.When the amount of carbon material added reaches 0.50 wt.%,the electrical properties of the composite material are the most excellent.The life cycle impact assessment was carried out by LCA method.The negative environmental impact of PA 6/11 obtained by polymerization in 1L reactor mainly came from the polymerization process,followed by the reactor cleaning and extraction process.Carbon emissions and energy consumption have increased slightly as CNTs or GR additives have increased.