The Preparation And Characterization Of Polyamide6/Polyether Amine Copolymer

Polyamide,commonly known as nylon,is the first synthetic fiber in the world.PA6,characterized by its ease of processing,dominates the thermoplastic industries and is widely used as an engineering plastic.It also has excellent comprehensive performances such as good mechanical properties,abrasion resistant,anti-corrosive properties and good lubricity.However,due to the poor impact properties under the circumstances of dry and low temperature,the application fields of PA6 are limited.Anyother related development includes the formation of fiber with special features of wear resistance,light weight,high strengh as well as high elastic recovery rate.But at the same time,it has poor heat resistance and can’t remain high strength when exposed to sunlight for a long time.Compared with cotton fibers,the ventilation and moisture absorption property of nylon are poor.So people may feel unventilate and be easy to get static electricity in nylon textile.Recently segmented block copolymers composed by introduction of a soft,flexible polymer into the PA6 matrix is a widely used modification method.A series of nylon modified copolymers with different properties were obtained by changing the structure,length and amount of the flexible segments.Polyether amine(PEA)is a kind of polymer which has polyether structure as its main chain and amine group as its terminal fuctional group.By implying it into PA6 as soft segment,the PA6/PEA copolymers can be used as super tough heat-resistant engineering plastics as well as plastic fibers with high strengh and high water absorption.In this research work,various proportions of PEA(wt% PA6)were introduced into PA6 through condensation both in 250 m L four neck flask under atmospheric pressure and 50 L reactionpolymerizer under high pressure.The optimun reaction conditions are as follows: first,the mixture reacts for 6h at 240℃ under 3~4 bar.Then it reacts for at least 4h at 250℃ under atmospheric pressure.The structure of copolymer was confirmed by FT-IR and verified by 1H-NMR.The results of GPC and the extractable content showed that copolymer relative molecular weight was range from14000 to 40000 with 10% extractable content.The thermal properties and crystalline structure were examined by DSC,TGA and XRD,which indicated that melting temperature,crystallization temperature and crystallinity appeared to unapparent decreased while increasing PEA content in copolymers.However,it did not affect the crystal type of PA6.The thermal decomposition temperature also decreased but still satisfied the molding temperature.It is believed that PEA soft segments scattered in PA6 hard chain and destoried its continuity,which decreased the hydrogen bond force between intramoleculars.The results obtained from capillary rheometer indicated that the PA6/PEA copolymer exhibited typical non-Newtonian fluid properties.The increase in non-Newtonian coefficients in the test temperature range is not obvious and the activation energy of the viscous flow is low,which indicated that the copolymer had a larger processing temperature range.The fiber modified with PEA showed lower mechanical properties,higher boiling water shrinkage,heat shrinkage than neat PA6 fiber but has better moisture regain,resistance and elastic resillience.As the draf ratio increasing,the initial modulus of the fiber increased and tensile strain decreased.When implying more PEA into PAT,the tensile strength and flexural strength of the polyamide 6 / polyether amine copolymer with higher molecular weight decreased,while the elongation at break increases and the impact strength increased.