Urethanes, poly rigid

Tough Compositions. The toughness of a thermoplastic, rigid poly(urethane) (PU) can be markedly improved by incorporating ABS resin. The ABS resin is mass-polymerized. 

Foam-blowing rigid poly-urethane CFC-ll Reduced CFC option 30-50 2.24 97... 

REPORT OF RESEARCH ON THE CHARACTERISTICS OF RIGID POLY-URETHANE FOAM FOR THERMAL INSULATION APPLICATIONS. TECH. REPT. 

For systems of rigid poly diacetylenes with functional or ionic side groups and car-boxylated or sulfonated polystyrene or sulfonated polyester-urea urethanes, molecular composites could be achieved by ionic interactions [51]. The blends exhibited no microphase separation and the miscibility on a molecular length scale was proven by infrared spectroscopic, dynamic mechanical and differential scanning calorimetry analysis. The molecular reinforcement amounted to up to 1 order of magnitude in compliance with a Halpin Tsai description and was achieved by only a few weight percent of the rigid compound. 

The low heat deflection temperature of PLA limits its use for several application fields, such as in packaging materials and electronic components. The introduction of rigid building blocks [63] or cross-links [64] is known, for instance, to increase the glass transition temperature and/or heat resistance of lactic acid based polymers. The effect of different amounts of comonomers in the prepolymers on the Tg and mechanical properties of poly(ester-urethane)s is demonstrated in Table 3.2. The heat resistance of poly(ester-ure-thane)s can be improved by the copolymerization of lactic acid with D,L-mandehc acid. This broadening of the operating temperature range is of clear practical importance. The incorporation of other comonomers that impede rotation and make polymer chains less mobile also causes an increase in Tg, even if the same comonomers can depress the rate of poly condensation [50]. 

A rigid poly(urethane) foam or poly(isocyanurate) foam can be prepared by reacting a poly(ol) and an isocyanate in the presence of a... 

Dichloro-l-fluoroethane was used as the blowing agent for the preparation of rigid poly(urethane) foams. However, this compound has the capability to destroy the ozone layer. So it has been decided to prohibit the use of this compound as a blowing agent. 

Although more environmentally acceptable blowing agents have come into use that are typically hydrohalocarbons, these are generally not as effective as those commonly used previously and there is, therefore, a continuing need for enhancements in the process of making rigid poly(urethane) foams and m the properties of the foams themselves. 

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