Blowing agent, agents

Blood sugar Blood urea nitrogen Blowers Blowing agent... 

Several more recent variations of the film-to-fiber approach result in direct conversion of film to fabric. The film may be embossed in a controlled pattern and subsequently drawn uniaxiaHy or biaxiaHy to produce a variety of nonwoven products (47). Addition of chemical blowing agents to the film causes fibrillation upon extmsion. Nonwovens can be formed directly from blown film using a unique radial die and control of the biaxial draw ratio (48)... 

Diethyl Ethylphosphonate. A Hquid compound introduced for appHcations similar to those of DMMP is diethyl ethylphosphonate [78-38-6] CgH O P. This material is claimed to be less susceptible to undesirable interactions with haloaHphatic components, such as blowing agents, or with amine catalysts. 

The use of CFCs as foam blowing agents has decreased 35% from 1986 levels. Polyurethanes, phenoHcs, extmded polystyrenes, and polyolefins are blown with CFCs, and in 1990 the building and appHance insulation markets represented about 88% of the 174,000 t of CFCs used in foams (see Foamed plastics). 

CFC-114 blowing agents and refrigerants HCFC-124 HCFC-142b blends / azeotropes HFCs... 

Chemical Stabilization. The chemistry of the system determines both the rate at which the polymer phase is formed and the rate at which it changes from a viscous fluid to a dimensionally stable cross-linked polymer phase. It also governs the rate at which the blowing agent is activated, whether it is due to temperature rise or to insolubilization in the Hquid phase. 

The type and amount of blowing agent governs the amount of gas generated, the rate of generation, the pressure that can be developed to expand the polymer phase, and the amount of gas lost from the system relative to the amount retained in the cells. 

The thermal conductivity of a cellular polymer can change upon aging under ambient conditions if the gas composition is influenced by such aging. Such a case is evidenced when oxygen or nitrogen diffuses into polyurethane foams that initially have only a fluorocarbon blowing agent in the cells (32,130,143,190,191,198-201). 

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