Preparation And Properties Of HDPE/PA6in Situ Micro-fibrillar Blends

The single-screw extruder of kind20, a cooling trough, two traction machines, and an automatic constant temperature heating barrel was used for this paper. In situ micro-fibrillar blend based on High Density Polyethylene (HDPE) and Nylon6(PA6) was prepared through melt extrusion-cold stretching-hot stretching processing. The effects of barrel temperature, screw speed of single-screw extruder, content of PA6, cold stretching temperature and time, hot stretching temperature, and hot stretching ratio on the morphology of extrudate were researched.The study results showed that the optimum barrel temperature for preparing in situ micro-fibrillar blend was200、230、250、210℃(the die), the content of PA6under20%, the extrusion die diameter was4mm, the optimum range of screw speed was30rpm-50rpm, the cooling water temperature was15℃, the cooling time was1s, the hot stretching temperature was75℃, and the heating mode was cylindrical air heating.The micro-fiber morphology study results showed that the specimens of scanning electron microscopy were prepared through quick impact fracture, packing with tetrafluoroethylene, and etching7min in the boiling xylene; with the increase of screw speed, the size of PA6microspheres decreased, and the dispersion was getting better and better; with the increase of hot stretching ratio, the number of micro-fiber and the aspect ratio gradually increased; under the same stretching ratio, the number of micro-fiber increased with the increase of the content of PA6.The melt flow ratio study results showed that under the same content of PA6, the vary of melt flow ratio of blend tend to low with the increase of aspect ratio of micro-fiber; under the same stretching ratio, the melt flow ratio of blend decreased significantly with the increase of content of PA6.The stress-strain performance of in situ micro-fibrillar blend study results showed that the stress-strain properties of blend gradually increased with the increase of content of PA6, and the tensile properties of blend increased by37.4%when the content of PA6was12%; when the content of PA6was4%, the stress-strain performance of blend was on the rise with the increase of draw ratio; the vary of impact properties tend to decline with the increase of content of PA6and tend to low-high with the increase of draw ratio.The compatibilizer study results showed that the compatibilizer improved the melt-extrusion stability of blend, strengthen the combination of PA6micro-fiber and the matrix, and improved the aspect ratio and the blend melt flow rate; compared with the blend without compatibilizer, the stress-strain performance of in situ micro-fiber blend was improved; compared to HDPE, the tensile strength of blend increased by55.3%and impact strength was also significantly improved when the content of PA6and HDPE-g-MAH was12%; the impact strength of blend was102.8KJ/m2and increased byl8.8%compared to HDPE.