Preparation, Structure And Property Of HDPE/PA6 Composites

High density polyethylene(HDPE)/polyamide6(PA6)/grafted polymer, HDPE/PA6/organic-montmorillonite (OMMT) and HDPE/PA6/OMMT/grafted polymer were preparedby melt-blending.The influences of containing of PA6,grafted polymer, OMMT and twodifferent surface treating agent on mechanical property, thermal property, friction and wearproperty, barrier and process properties of composites were investigated, and the mechanismwas researched as well.HDPE/PA6/grafted polymer composites have been prepared by melting extrusion, andstudied for a large rang of PA6 content (from 0 to 40wt%). The results showed with addingPA6, the tensile strength of composites was increased, but their impact strength wasdecreased at the same time.The barrier property to xylene was enhanced, meanwhile theprocessing and friction property were improved.The study dealt with the effectiveness of maleic anhydride(MAH) or maleicanhydride(MAH) and styrene(St) grafted HDPE as compatibilizer precursor(CP) for HDPEand PA6.The CP was produced by grafting MAH(St) onto HDPE in the melt.Thecompatibilizing efficiency of HDPE-g-MAH and HDPE-g-(MAH-co-St),as revealed byFourier transform infrared spectrum (FTIR),differential scanning calorimetry(DSC) and theproperties of compatibilized blends,has been shown that HDPE-g-(MAH-co-St) was moreefficient than HDPE-g-MAH.The mechanical properties, friction and barrier properties ofHDPE/PA6(70/30) blends compatibilized with HDPE-g-(MAH-co-St) have been compared with the blends compatibilized with HDPE-g-MAH.The results showed that the strongcompatibilizing efficiency of CP exhibited better properties.The microstructure and crystallization property of HDPE/PA6/OMMT nano-compositeswere characterized by XRD, TEM, SEM and DSC. Nano-OMMT can be prepared by meltingintercalation that was proved. This study investigated the role of layered silicate clay MMTon morphology development in chaotic mixing of two immiscible polymers, HDPE andPA6.The study showed that clay particles helped to produce droplets of much smaller sizeand with narrower size distribution due to their direct in influence on the breakup of PA6domains. The clay particles reduced interfacial tension between HDPE and PA6 phases. As aconsequence, HDPE in turn broke into small droplets with 7phrMMT.This results indicatedthat clay particles did change the structure of HDPE and PA6 phases.In addition to improvement of mechanical property, HDPE/PA6 nanocomposites heldattractive protential for the development of novel material with improved barrier and frictionproperties,as larger interlayer spacings and formation of exfoliated anisotropic nanosilicateswith high aspect ratio.The results showed the friction coefficient and the wear loss effectivelywere lowered when adding 1phr OMMT, and the barrier property was reinforced whenOMMT content between 1phr and 3phr.The mechanical properties of composites materialswere improved most significant, just the content of OMMT was 3phr.XRD and TEM analysis showed that the interlayer distance of OMMT was not enlarged bygrafted polymer,which indicated that grafted polymer prevented OMMT from beingintercalated or exfoliated in the PA6 phase.But when adding 6phr grafted polymer, themechanical properties was best, while the friction property of composites can be improved byfilling grafted polymer. It was shown from the results that the friction coefficient and wearloss of composites with 9phr grafted polymer were just 57.1% and 62.5% of compositeswithout grafted polymer, respectively.The HDPE/PA6/MMT composites have been studied by X-ray diffraction (XRD). MMTwas dealt with alkytrim-ehylammoniumbromide surfactant,of different chain lengths(n=16and 18), which called C16-MMT and C18-MMT.The surfactant chain length and the dspacing of the composites were observed that C18 didn't contribute to the widening of theMMT interlayer. The d space of MMT was decreased when adding grafted polymer. The results indicated the mechanical properties of Composites with C16-MMT were better thanthe composites with C18-MMT.The water absorption of composites with C16-MMT orC18-MMT was increased, while C16-MMT higher than C18-MMT.It was shown from theresults that adding grafted polymer could improve the mechanical property, water absorptionand friction property.