Structure and physicomechanical properties of high density polyethylene filled during polymerization

Abstract

The morphology of supermolecular structures in polymerization filled polyethylene prepared with the TiCI,/(CsH,),AICl catalyst system and chalk and marble powder as fillers has been investigated. It is established that the lamellar crysta!lites envelop the filler particles, the bases of the lamellae being parallel to the filler surface. Up to the investigated filling degree (21.7 to 23.5 wt%), the formed supermolecular structures affect favourably the physicomechanical properties of the polymer filled during polymerization. A mechanism of the formation of the structures is proposed. Struktur und physikalkch-mechanische Eigenschaften uon wlihrend der Polymerhation gefiilltem Polyelhylen hoher DichteDie Morphologie und der Mechanismus der Bildung ubermolekularer Strukturen von wahrend der Polymerisation gefulltem Polyethylen wurden untersucht. Als Katalysatorsystem wurde TiCI,/(C,H,),AlCl eingesetzt, als Fullstoffe dienten Kreide und Marmorpulver. Es wurde festgestellt, daB die Lamellenkristalle die Fiillstoffteilchen umhiillen, wobei die Lamellenbasis parallel zur Oberflache des Fullstoffs liegt. Bis zum untersuchten Fullungsgrad von 21,7 bis 23,5 Masse-% wirken sich die iibermolekularen Strukturen gunstig auf die physikalisch-mechanischen Eigenschaften des polymerisationsgefiillten Polyethylens aus.

Effect of Processing on Ductility and Strength of Kevlar/Polyethylene Composites

“…) * for (13) The average strength of composites with 3D randomly oriented short fibers (σ c-3D ) is obtained as:…”

“…An effective way of producing 'isotropic composites' is to use randomly oriented short reinforcing fibers. For polyolefins, a polymerizationfilled technique provides an effective way to improve the mechanical properties [1][2][3][4][5][6][7][8][9][10][11][12][13] . Preparation of polymerization-filled composites consists of 1) fixing a Ziegler-Natta (or metallocene) catalyst on the surface of the reinforcing agent and 2) monomer polymerization (olefins) from the supported catalyst on the surface of the reinforcing agent.…”

“…There are several advantages of the polymerization filled technique: 1) more uniform distribution of filler throughout the polymer, and 2) optimum opportunity for the polymer to wet and to be adsorbed on the filler surface. [1][2][3][4][5][6][7][8][9][10][11][12][13] In a previous study 14 , short fiber composites were prepared using two techniques: polymerization filled composites (PFC) and melt blended composites (MBC). The fiber aspect ratio distribution, break strain, critical aspect ratios and Young's modulus of the composites were carefully analyzed.…”