The Preparation Of MAH Grafted Copolymer And The Toughening Of PA1012

PA1012,is widely used in automotive parts,medical equipment,military products and other fields,but its molecular structure with hydrophilic group-CO-NH-key,which greatly enhances the water absorption capacity of nylon,and poor mechanical properties that making its application range also severely limited,so it is the most practical way to change the focus of the researchers.The purpose of this study is to get the core-shell structure of butyl acrylate grafted maleic anhydride(ACR-g-MAH)and styrene-maleic anhydride(SMA)to toughen PA1012 and further study its toughening effect and mechanism.The ACR-g-MAH copolymer was synthesized by emulsion polymerization,with PA1012 prepared blends,the FTIR characterization showed a unique C=O stretching vibration peak at 1634 cm-1 and 1694 cm-1,successfully confirmed that MAH has been grafted onto ACR.When the ACR-g-MAH core-shell ratio was 80:20,the ratio of MAH in the shell was 3%,the amount of ACR-g-MAH was 15 phr,the blends have maximum impact strength of 209.1 J/m,and the tensile strength changed little,so comprehensive mechanical properties better.DMA showed that the tan? of the nuclear phase PBA increased and the storage modulus of ACR decreased after grafting MAH.TG test showed that proper grafting MAH was beneficial to improve the heat resistance of PA1012/ACR.SEM found that PA1012 etching surface was still smooth,while the surface of the blends caused by ACR-g-MAH off the hole,which indicated that ACR-g-MAH dispersed better in PA1012,the interface bonding effect and mechanical performance were enhanced to toughen PA1012.SMA and PA1012 were melt blended to prepare PA1012/SMA blends,when the SMA content was 5% of the blending system,the notched impact strength is 1463 J/m,which was 14.5 times of the pure PA1012 impact strength.SEM found that PA1012 etching surface was still smooth,while the surface of the blends caused by SMA off the hole,which suggested that SMA dispersed better in PA1012.It can be found that by SEM when the content of SMA was 4% and 5%,the impact fracture surface show "lamellar" and yield fibrils,which is ductile fracture characteristics,and obtain the toughening effect on PA1012.DSC characterization showed that when the cooling rate was constant,after adding SMA,the temperature of the blend was higher than that of PA1012,and it was proved that SMA played the role of heterogeneous nucleating agent.Crystalline melting behavior and XRD show that PA1012 has two crystal forms,? crystal form and ? crystal form,after adding SMA,the ? crystal form is obviously promoted and the ? crystal growth is weakened.