Study On Preparation And Properties Of Thermally Stimulated Shape Memory Of HDPE/PET Blends

Thermally stimulated shape memory polymer is a new type of functional material which has attracted great interest in recent years.In this paper,based on the design and modification of polymer materials,the high density polyethylene(HDPE) and polyethylene terephthalate(PET) blends which possessed thermally stimulated shape memory effect were prepared by means of reactive melt extrusion using ethylene-butyl acrylate-glycidyl methacrylate terpolymer(EBAGMA),HDPE-g-GMA and HDPE-g-(GMA-co-St) as three kinds of different reactive compatibilizers.The effects of several factors,such as the ratio of components,content and species of the compatibilizers on the shape memory effect, mechanical,rheological and thermal properties of blends were systematically investigated. The relationship between phase morphology and properties of blends were also studied by SEM,DMA,DSC and FTIR.In the stystem of HDPE/PET/EBAGMA blends,the results showed that the epoxy groups of glycidyl methacrylate(GMA) in EBAGMA reacted with the terminal hydroxyl and earboxyl groups of PET,giving rise to in situ compatibilization to the HDPE/PET blends,So the shape memory effect and combined mechanical properties of the blends were improved significantly while the phase morphology and processability were also promoted. Further more,they all possessed good thermal property.The experiment results also showed that there was an optimal proportion in HDPE/PET/EBAGMA blends,which was 90/10/5,and the izod impact strength was increased 400%,while the tensile strength and elongation at break were increased 25%and 50%respectively.When the content of PET was 5wt%-20wt%in the matrix with 5 phr EBAGMA,the shape recovery ratios of blends all achieved 95%at least and the response temperature(about 130℃) of the stystem was related with the melting temperature of HDPE.In the stystem of HDPE/PET/HDPE-g-GMA blends,the compatibilizers,HDPE grafted by GMA and GMA/St were prepared by melt-grafting.FTIR analysis confirmed the presence of the grafting structure.It showed that the GMA/St bi-monomer melt grafting HDPE is better than GMA single-monomer on grafting yield and compatibility to the HDPE/PET blends.As a result,the shape memory effect,mechanical,rheological properties and phase morphology of HDPE/PET/HDPE-g-(GMA-co-St) blends were superior to those of HDPE/PET/HDPE-g-GMA blends.