Impact strength of polyphenylene ether-linear polyester articles

#This invention relates to the preparation of resinous articles of high impact strength, and in particular to the preparation of such articles from compositions comprising polyphenylene ethers and linear polyesters.

#The polyphenylene ethers are a widely used class of thermoplastic engineering resins characterized by excellent hydrolytic stability, dimensional stability and dielectric properties. They are also resistant to high temperature conditions under many circumstances. Because of the brittleness of many compositions containing polyphenylene ethers, they are frequently blended with impact modifiers such as elastomers to form molding compositions.

#A disadvantage of the polyphenylene ethers which militates against their use for molding such items as automotive parts is their low resistance to non-polar solvents such as gasoline. For increased solvent resistance, it would be desirable to blend the polyphenylene ethers with resins which have a high degree of crystallinity and therefore are highly resistant to solvents. Illustrative of such resins are the linear polyesters, especially the poly(alkylene terephthalates). However, such blends frequently undergo phase separation and delamination. They typically contain large, incompletely dispersed polyphenylene ether particles and no phase interaction between the two resin phases. Molded parts made from such blends are typically characterized by extremely low impact strength.

#The preparation of functionalized polyphenylene ethers for use in the invention is illustrated by the following examples. In these and other examples herein, all parts are by weight.

#A solution of 100 parts of a poly-(2,6-dimethyl-1,4-phenylene ether) having a number average molecular weight of about 20,000 and an intrinsic viscosity in chloroform at 25.degree. C. of 0.48 dl./g., 2 parts of TAAC and 5 parts of dimethyl-n-butylamine in 500 parts of toluene was heated at 95.degree. C. for 3 hours, with stirring. The product was precipitated by addition of methanol, redissolved in toluene and reprecipitated, and dried under reduced pressure. It was shown by infrared spectroscopy to be the desired anhydride-functionalized polyphenylene ether.

#A mixture of 99 parts of the polyphenylene ether used as a reactant in Example 1 and 1 part of maleic anhydride was extruded on a single-screw extruder at temperatures in the range of 120.degree.-330.degree. C. The extrudate, comprising an anhydride-functionalized polyphenylene ether, was quenched in water, pelletized, dissolved in chloroform, precipitated with methanol, filtered and vacuum dried at 60.degree. C.