USING REACTIVE BLOCK COPOLYMERS AS CHAIN EXTENDERS AND SURFACE MODIFIERS

摘要

A process is provided for making a reactive-block-copolymer chain extender, comprising reacting an acrylic monomer that has functional groups with one or more vinyl monomers in the presence of a free radical initiator and a stable free radical to form a reaction product that includes residual unreacted acrylic monomer, and reacting one or more vinyl monomers with the reaction product to form a second block that incorporates the residual unreacted acrylic monomer. The reactive-block-copolymer chain extender is reacted with a polymeric material, such as recycled polyethylene terephthalate (PET), that has functional groups, and polymer chains in the polymeric material bond to the reactive- block-copolymer chain extender, which serves as a backbone for coupling polymer chains together for increasing the average molecular weight of the polymeric material, thereby improving the quality of the polymeric material. The chain extender can be reacted with polymeric materials that have a lower-than-desired molecular weight, such as due to low- quality production or due to recycling, to couple polymer chains of the polymeric material together, which effectively increases the average molecular weight of the polymeric material, increasing intrinsic viscosity and improving properties of the polymeric material. The chain extender is particularly useful with polymeric materials that have reactive functional groups, such as polyesters, and is also useful as a compatibilizer for polymeric materials that do not have reactive functional groups, such as polyethylene, polypropylene and polystyrene. The present invention further provides a process for modifying the properties of a polymeric material, particularly its surface properties. A reactive block copolymer (RBC) property modifier can be made with particular functionalized acrylic monomer and vinyl monomer, which may or may not contain functional groups, and the RBC property modifier can be mixed and/or reacted with a polymeric material to change the properties of the polymeric material, particularly the polarity and surface energy of the polymeric material.