Elastomeric fibers structure

The structure of elastomeric fibers is similar to that illustrated for polyurethane foams. 

Classifications, physical structure, and chemical structure of elastomeric fibers... 

A clear trend is recognized between fiber polarity and moisture uptake. The amount of polar amide (NH-CO) linkages and hydroxyl (OH) pendant groups into the methylene chain structures of polyamide and poly(vinyl alcohol) fibers, respectively, render them significantly more moisture absorbent (4-5%) than the polyolefins and elastomeric fibers (less than 0.1%). Densely packed polymer networks, as in the cases of polyester, poly(vinyl chloride), and particularly Kevlar fibers, exclude the entry of water molecules, again resulting in low moisture content. 

Illustration of fine structure expected in elastomeric fibers, composed of blocks of crystal I izable hard segments and non-crystallizable coiled soft segments. 

The results using SRIM procedure have shown that a channel distribution system in combination with equidistant multiple inlet holes facilitates the impregnation of reinforcement fiber structure with an elastomeric polymer matrix. Symmetric arrangement of the channels gives symmetric polymer flow into the cavity. This makes fastening of the reinforcement structure to the mold during resin injection unnecessary in order to prevent dislocation of the fiber mat inside the cavity. 

The first elastomeric protein is elastin, this structural protein is one of the main components of the extracellular matrix, which provides stmctural integrity to the tissues and organs of the body. This highly crosslinked and therefore insoluble protein is the essential element of elastic fibers, which induce elasticity to tissue of lung, skin, and arteries. In these fibers, elastin forms the internal core, which is interspersed with microfibrils [1,2]. Not only this biopolymer but also its precursor material, tropoelastin, have inspired materials scientists for many years. The most interesting characteristic of the precursor is its ability to self-assemble under physiological conditions, thereby demonstrating a lower critical solution temperature (LCST) behavior. This specific property has led to the development of a new class of synthetic polypeptides that mimic elastin in its composition and are therefore also known as elastin-like polypeptides (ELPs). 

Stereoregular polymers also have symmetrical structures, and the helices of isotactic polymers can be close-packed to produce highly crystalline material. Iso-tactic polypropylene is crystalline and an important fiber-forming polymer, whereas the atactic form has virtually no crystalline contort and has little value as a fiber indeed, it is considerably more elastomeric in nature. 

Synonyms Acrylic Acrylic fiber Acrylic polymer Acrylic sheet Definition Thermoplastic polymer or copolyrner of acr ic acid, methacrylic acid, esters of these acids, or acrylonitrile Properties Varies from hard to brittle solids to fibrous elastomeric structures, to viscous liqs. able to transmit light for sheet and rod forms Toxicology Dust may cause skin, eye, and respiratory tract irritation TSCA listed... 

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