Low density particles of polyphenylene ether resins

A process for producing low density polyphenylene ether resin compositions wherein said polyphenylene ether resin may be admixed with up to approximately 98 weight percent of an alkenyl aromatic resin based upon the weight of both resins taken together, comprising the steps of:

• incorporating a blowing agent in said resin composition wherein the blowing agent is a volatile liquid or gas selected from the group consisting of C.sub.4 to C.sub.7 aliphatic hydrocarbons and C.sub.1 to C.sub.2 fluorocarbons capable of being absorbed by the resin composition and which will vaporize at a temperature below the glass transition temperature of the resin composition, and which is present in an amount sufficient to effect expansion of the resin composition in the next step;
• expanding the resin composition containing the blowing agent by heating to a temperature between about 100.degree. and 210.degree. C.;
• thereby providing an polyphenylene ether resin composition having a bulk density less than about 20 lbs./ft.sup.3.