Polyethylene self-reinforced

Pornnimit B and Ehrenstein G W (1989) Self-reinforced polyethylene produced by extrusion, Kunststoffe 79 631-636. 

Lei J, Jiang C and Shen K (2004) Biaxially self-reinforced high-density polyethylene prepared by dynamic packing injection molding. I. Processing parameters and mechanical properties, J Appl Polym Sci 93 1584-1590. 

Guan Q, Shen K, Ji J and Zhu J (1995) Structure and properties of self-reinforced polyethylene prepared by oscillating packing injection molding under low pressure, J Appl Polym Sci 55 1797-1804. 

Guan Q, Lai F S, McGarthy S P, Chiu D, Zhu X and Shen K (1997) Morphology and properties of self-reinforced high density polyethylene in oscillating stress field. Polymer 38 5251-5253. Kalay G, Sousa R A, Reis R L, Cunha A M and Bevis M J (1999) The enhancement of the mechanical properties of a high-density polyethylene, J Appl Polym Sci 73 2473-2483. 

Pomnimit, B., and Kassel, G.W.E. Self-Reinforcing Polyethylene Produced by Means of Extrusion. Kunststoffe, pp. 43-46, July 1989. 

Pomnimit B, Ehrenstein GW (1991) Extrusion of self-reinforced polyethylene. Adv Polym Technol 11 91-98... 

As described earlier, the main prerequisite for the creation of high performance self-reinforced polymer composites is a thermoplastic polymer fibre with the necessary mechanical properties to make the creation of the final composites attractive. Ultrahigh molecular weight polyethylene (UHMWPE) fibres with veiy high mechanical properties, produced by gel spinning, became commercially... 

Table 2 Mechanical properties of polyethylene-based self-reinforced polymer composites, as described in the literature... 

Shalaby SW, Deng M, inventors Poly-Med, Inc., assignee. Self-reinforced ultra-high molecular weight polyethylene composites. United States Patent No. 5,824,411 1998. 

PC is more resistant to strong acids but is less stable than polyterephthalates (PET, PBT) to benzene and methanol. PET, polyethylene terephthalate, is a hard, stiff homopolymer, whilst PBT, polybutylene terephthalate is somewhat softer. Further materials in this group include, i) thermoplastic poly (ether) ester elastomers, included in the TPE grouping, ii) amorphous polyarylates, and Hi) self-reinforced crystalline polyarylates (LCP). Polycarbonate may be blended with various styrenics (PC/ABS, PC/ASA, PC/SMA). 

CSPE. Chlorosulfonated polyethylene (CSPE), a synthetic mbber manufactured by DuPont, is marketed under the name Hypalon. It can be produced as a self-curing elastomer designed to cure on the roof. The membrane is typically reinforced with polyester and is available in finished thicknesses of 0.75 to 1.5 mm. Because CSPE exhibits thermoplastic characteristics before it cures, it offers heat-weldable seams. After exposure on the roof, the membrane cures offering the toughness and mechanical set of a thermoset. The normal shelf life of the membrane for maintaining this thermoplastic characteristic is approximately six months. After the membrane is fully cured in the field, conventional adhesives are needed to make repairs. 

Thioglycolic acid is stored in reinforced polyethylene or polypropylene tanks or containers. It is advisable to keep thioglycolic acid at low (<10° C) temperature to slow down self-esterification. The same care must be taken with dmms or tank tmeks. Dmms are made of polyethylene or polyethylene-lined steel. For transport, thioglycolic acid is classified as a corrosive and toxic liquid. The handling of thioglycolic acid requires the usual precautions observed for strong acid and corrosive chemicals. 

During the last decade many new roofing materials were introduced which are applied in the form of weldable membranes, liquid curable materials, self-adhesive products, and torchable materials. These materials are produced from numerous polymers such as, PVC, chlorinated polyethylene, chlorosulfonated polyethylene, EPDM, acrylics, bitumen, polymer-reinforced bitumen and several other materials. It is beyond the scope of this book to analyze compositional changes in these materials. We will provide a brief overview. 

---