Polyphenylene oxide, modified foams

Table VI. Comparison of Needle-Flame Test Results and Oxygen Indices for Modified Polyphenylene Oxide Structural Foam Samples...

Coatings can interact with the substrate as shown with zinc on modified-polyphenylene oxide structural foam. Examination of zinc on modified-polyphenylene oxide has been undertaken to ascertain the origin of the synergism and is reported separately. The presence of zinc shows an increase in char, and a decrease in low molecular weight volatiles at pyrolysis temperatures versus the uncoated substrate. 

The substrates tested alone have substantially different values. Polycarbonate (1/4 inch) structural foam has an of 27.5, modified-polyphenylene oxide (1/4 inch), 84.4, and RIM polyurethane (1/2 inch), 173.3. These values compare with 164.4 for 1/4 inch hardboard and 139.1 for 1/4 inch plywood. A comparison of graphite, nickel, and copper/aciylic coatings on polycarbonate and modified-polyphenylene oxide substrates illustrate a dramatic result. Despite a factor of 3 difference in substrate performance, the Q and Fs values for the coated samples are very similar. The Q for the modified-polyphenylene oxide samples are 0.7 to 0.5 that of the uncoated sample. One would expect a similarity in Fs for the coated sample, but such a reduction in Q is dramatic. Both Q and Fs are determined by the 2 mil surface. 

Figure 4. Continued. NBS Smoke Chamber results (flaming) for modified-polyphenylene oxide and RIM polyurethane structural foam.

In 1982 the leader in structural plastics used for structural foams parts was modified polyphenylene oxide (NORYL ), accounting for almost three-quarters of all material usage. Polycarbonate held a strong second materials position, followed by ABS, with polystyrene next (5). 

Noryl . [GE Plastics GE Plastics Ltd.] Modified polyphenylene oxide resins engineering resin for inj. mcdding, ex> trasitm, structural foam used for computers, business equip., automotive, elec., electronics, construction, telecommunications, tqppliances, and other industries. 

Modified Poiyphenyiene Ether Thermoplastic polyphenylene ether alloys with impact polystyrene. Has good impact strength, resistance to heat and fire, but poor resistance to solvents. Processed by injection and structural foam molding and extrusion. Used in auto parts, appliances, and telecommunication devices. Also called MPE, MPO, and Modified Polyphenylene Oxide. 

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