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For example, atactic polypropylene is usually amorphous and transparent while syndiotactic polypropylene, which has crystallinity ~50%, is opaque. [30] Crystallinity also affects dyeing of polymers: crystalline polymers are more difficult to stain than amorphous ones because the dye molecules penetrate through amorphous regions with greater ease.
Kevlar (para-aramid) [2] is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora.Developed by Stephanie Kwolek at DuPont in 1965, [3] [2] [4] the high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tires.
In the context of textile applications, PET is referred to by its common name, polyester, whereas the acronym PET is generally used in relation to packaging. [citation needed] Polyester makes up about 18% of world polymer production and is the fourth-most-produced polymer after polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC).
Polyester resins are synthetic resins formed by the reaction of dibasic organic acids and polyhydric alcohols. Maleic anhydride is a commonly used raw material with diacid functionality in unsaturated polyester resins. [1] Unsaturated polyester resins are used in sheet moulding compound, bulk moulding compound and the toner of laser printers.
The polymer is formed by free-radical polymerization in aqueous suspension. The fiber is produced by dissolving the polymer in a solvent such as N,N-dimethylformamide (DMF) or aqueous sodium thiocyanate, metering it through a multi-hole spinneret and coagulating the resultant filaments in an aqueous solution of the same solvent (wet spinning) or evaporating the solvent in a stream of heated ...
The ceramic and metallic window films usually cost 50-100+ percent more than regular window film but they can reduce energy transmission by as much as 80 percent. [4] Ceramic window films cost slightly more but provide a substantial increase by reflecting and absorbing infrared radiation (IR or radiant heat).
The 50/30/20 budget is a simple budgeting method. You limit fixed expenses to 50% of income, save 20%, and can spend the remaining 20%. It can be hard to stick to these percentages with an average ...
A difficult aspect of plastic deterioration is that one cannot see what types of chemical reactions are occurring in the interior of an object, or easily identify the makeup of proprietary plastic composites. Many plastics will give off a distinct odor, ooze liquids, or will begin to shrink or crack in some way as they age. [12]