COMPOSITIONS CONTAINING POLYPHENYLENE ETHER AND/OR POLYSTYRENE HAVING IMPROVED TRIBOLOGICAL PROPERTIES AND METHODS FOR IMPROVING TRIBOLOGICAL PROPERTIES OF POLYPHENYLENE ETHER AND/OR POLYSTYRENE COMPOSITIONS
View Patent ↗Internally lubricated polymer compositions containing a styrene- and/or polyphenylene ether-containing polymer, an olefin-containing polymer, and a compatibilizer are provided. The olefin-containing polymer, which is present in the compositions in about 3 to about 30 weight percent, provides internal lubrication and improves the tribological properties of the compositions compared with the styrene- or polyphenylene ether-containing polymer alone, as determined by wear measurements. Preferred compositions exhibit wear factors less than about 130×10 −11n mm 5 /Pa-m. A preferred composition includes a blend of polystyrene/polyphenylene ether, linear low density polyethylene, and styrene-ethylene-butadiene-styrene. Methods are also provided for improving tribological properties of styrene- and/or polyphenylene ether-containing base polymers by incorporating into the base polymers at least one olefin-containing polymer and at least one compatibilizer, or by incorporating at least one substantially halogen-free internal lubricant.
1. A composition comprising:
(a) a base polymer selected from the group consisting of a polymer comprising styrene and a polymer comprising polyphenylene ether;
(d) a polymer consisting essentially of linear low density polvethylene for providing internal lubrioation; and
(c) a compatibilizer;
wherein the composition has a wear factor of less than about 65×10 31 11 mm 5 /Pa-m.
2. The composition according to claim 1 , wherein the polymer consisting essentially of linear low density polvethylene comprises about 5 to about 30 weight percent of the composition based on a total weight of the composition.
3. The composition according to claim 2 , wherein the polymer consisting essentially of linear low density polyethylene comprises about 5 to about 25 weight percent of the composition based on the total weight of the composition.
4. The composition according to claim 1 , wherein the base polymer is selected from the group consisting of homopolymers and copolymers of styrene, acrylonitrile-butadiene-styrene and styrene-acrylonitrile.
5. The composition according to claim 1 , wherein the base polymer is a blend of the styrone polymer and the polyphenylene ether.
6. The composition according to claim 1 , wherein the compatiblizer comprises a styrene/olefin copolymer.
7. The composition according to claim 6 , wherein the styrene/olefin copolymer is selected from the group consisting of polystyrene-ethylene-butadiene-styrene, styrene-ethylene interpolymer, styrene-butadiene rubber, and polystyrene-ethylene-propylene.
8. The composition according to claim 1 , wherein the compatibilizer comprises about 1 to about 20 weight percent of the composition based on a total weight of the composition.
9. The composition according to claim 8 , wherein the compatibilizer comprises about 3 to about 10 weight percent of the composition based on the total weight of the composition.
10. The composition according to claim 1 , wherein the ratio of the weight of the polymer consisting essentially of the linear low density polyethylene to the weight of the compatibilizer is about 0.5:1 to about 10:1.
11. The composition according to claim 1 , wherein the base polymer comprises a blend of polyphenylene ether and polystyrene, and wherein the compatibilizer comprises polystyrene-ethylene-butadiene-styrene or a copolymer of styrene and propylene.
12. The composition according to claim 1 , further comprising:
(d) at least one additive selected from the group consisting of a filler, a reinforcing agent, an additional lubricant, a coloring agent, a processing aid, an impact modifier, a plasticizer, a slip agent, an ultraviolet absorber, an ultraviolet stabilizer, a flame retardant, a mold release agent, a flow modifier and a heat stabilizer.
13. The composition according to claim 12 , wherein the at least one additive is selected from the group consisting of carbon fiber, carbon powder, glass fiber, glass beads, aramid fiber, polyethylene terephthalate fiber, stainless steel fiber, ceramic fiber, ceramic powder, wollastonite, talc clay, mica, a pigment, a stearate, a wax, molybdenum disulfide, and an oil.
14. The composition according to claim 12 , wherein the at least one additive comprises a flame retardant.
15. A molded article prepared from a composition comprising:
(a) a base polymer selected from the group consisting of a polymer comprising styrene and a polymer comprising polyphenylene ether;
(b) a polymer consisting essentially of linear low density polyethylene for providing internal lubrication; and
(c) a compatibilizer;
wherein the composition has a wear factor of less than about 65×10 −11 mm 5 /Pa-m.
16. An article comprising the composition of claim 1 .