Polyamides, grafted with poly

Scheme 36 Synthesis of polyamide grafted with poly(THF)...

In this method the active hydrogen of the polymer is utilised to form graft copolymers. Polyamide is grafted with poly(ethylene oxide) as shown below ... 

Because the free radical initiated graft reaction can also lead to the cross-linking of polyethylene, copolymers of ethylene and with acrylic acid (184,185), glycidyl methacrylate (184,186), methacrylic acid and 10-undecenoic acid (187-189) were synthesized to compatibilize polyethylene/polyamide blends. The poly (ethylene-co-methacrylic acid) ionomers neutralized by sodium (184) and zinc (45,118,190-192) has also used as compatibilizers. High energy irradiation, used to modify the surface of fibers or films at beginning, was also used to compatibilize the polyethylene/polyamide blends (193-196). 

Core-shell impact modifiers have also been reported as impact modifiers for engineering polymers. MBS impact modifiers with a SBR core, a polystyrene middle layer and an outer layer of MMA copolymers with glycidyl methacrylate, acrylamide or methacrylic acid functional monomers were evaluated in PC/PBT blends [104]. Optimal results were obtained with 60 wt% SBR content in the MBS and a modest amoimt of a functional monomer in the MMA copolymer shell. Core-shell impact modification of polycarbonate [105] (PMMA grafted on poly(n-butyl acrylate) and PBT[106] (SAN grafted onto a butadiene based rubber) have been reported. A comprehensive review of core-sheU impact modification of various polymers (PMMA, PVC, PC, PBT, PET, polyamides, thermoplastic blends, thermosets) has been presented by Cruz-Ramos [107]. 

The first sample is a reactive poly(tetrafluoroethylene)/polyamide 6 (PTFE/ PA) blend [43]. When mixing PTFE micro-powder and PA in an extruder at about 280°C, relatively large PTFE particles occur in the final product because of immiscibility. By irradiation with electrons in air reactive groups in the PTFE powder are formed. These functionalised particles react with the molten PA in the extruder, and graft copolymers are formed, improving the compatibility of the components. At the same time a decrease in PTFE particle size proportional to the irradiation dose can be observed, and a PTFE/PA compound with better properties is produced. 

Polyamide copolymers containing a macromolecular graft substituent were prepared by condensing 4-amino-benzoic acid or a mixture of 1,4-phenylene diamine and adipic acid with 33%, 66%, and 90% 5-(poly(n-butylacrylate)cysteine macromonomer. A second macromolecular monomer, 5-(poly(methyl methacrylate)-cysteine, was also prepared and free radically copolymerized with perfluoromethyl methacrylate. 

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