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Investigation of POE Improving Low-temperature Toughness of Transparent Polypropylene for Medical Purpose

Author: ZhaoHaiYan
Tutor: DingRui
School: Shandong University of Technology
Course: Materials Science
Keywords: POE Medical transparent PP Blends Low-temperature toughness Nucleating agent
CLC: TQ325.14
Type: Master's thesis
Year: 2008
Downloads: 214
Quote: 3
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Abstract

Transparent polypropylene is rapidly developing a transparent polymer for medical products the largest raw material. Since the polypropylene products easy to brittle fracture at low temperatures, winter disposable medical devices in the process of transport and use of our northern great loss. Although many studies have reported on the PP toughening but no medical polypropylene random copolymer (Polypropylene Random Copolymer for Medical Purpose, hereinafter referred to as instead of medical PPR) toughened reported. Medical PPR products adapted to the cold climate of the northern part of the country, Japan's Mitsui Chemicals production of polyolefin elastomer POE low temperature toughening the blending modification process method and mechanism of the medical PPR. First, the refining process is carried out using weak shearing the blend, the blend prepared by different proportions of two grades the POE and Medical PPR, tableting sample preparation by dynamic mechanical analysis (DMA) to predict the POE PPR significant low-temperature the toughening effect; thus impact, tensile test to test and verify this prediction. The results show that, POE PPR has good low temperature toughening effect, at -20 ° C and -10 ° C, POE content of 15 parts by mass, DF640 POE impact performance than pure PPR increased by about 43 times under the same temperature conditions, DF710 POE impact strength than pure PPR increased about 35-fold; DF640 POE low temperature toughness than DF710-POE. Judging from the SEM cross-section observation, POE toughening mechanism of PPR meets crazes - shear yield theory. Thereafter, using a strong shear effect of twin-screw extrusion process for blending. Select the screw speed (230r/min) and an extrusion temperature (210 ° C), extrusion grades for the DF640 POE PPR by different proportions of the blend is prepared for injection specimen on the impact properties of the test piece, the pull-up tensile properties, dynamic mechanical behavior, rheological behavior, crystalline melting behavior and SEM cross-sectional images. Compared the extrusion process and a refining process is the obtained sample performance. The results show that the strong shearing action of the twin-screw extruder process proceeds sample in low temperature toughness, tensile properties and processability are superior refining process is. Finally, in order to to improve of POE toughened PPR specimen transparent performance in a twin-screw extrusion process, the class to dibenzylidene sorbitol (DBS) nucleating agent and DF640 POE PPR a modification, When the DBS content as 0.3 wt% blends in low temperature toughness, rigidity, transparency, etc. the best overall performance.

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CLC: > Industrial Technology > Chemical Industry > Synthetic resins and plastics industry > Polymer resin and plastic > Polyolefin plastic > Polypropylene
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