Grafting reaction conditions

Cotton linters and viscose grade wood pulp were grafted with acrylamide using the xanthate method. The effects of monomer concentration, reaction time, hydrogen peroxide concentration, reaction temperature, and liquor ratio on the grafting process were studied. Optimum conditions for the grafting reaction were established [26]. 

Chitosan is the main structural component of crab and shrimp shells. Chitosan contains both reactive amino and hydroxyl groups, which can be used to chemically alter its properties under mild reaction conditions. Al-acyl chitosans were already reported as blood-compatible materials. UV irradiation grafting technique was utilized to introduce obutyrylchitosan (OBCS) onto the grafted SR film in the presence of the photosensitive heterobifunctional cross-linking agent. The platelet adhesion test revealed that films grafted on OBCS show excellent antiplatelet adhesion. 

Trapped radicals on samples with different storage conditions and reaction conditions are usually determined by ESR. Modification of PVC by radiation-grafting technique is an attractive method to improve the mechanical strength, printing ink adhesion, and adhesive receptance. Wang... 

Table 5 Summary of the reaction conditions for poly(N-vinylcaprolactam) (PVCL) grafted with MAC11EO42 [181]... 

It is a well-known fact that the mechanical properties of fluoropolymers, especially perfluoropolymers, degrade dramatically under irradiation. Nevertheless a considerable improvement of the mechanical properties of the final grafted copolymers was observed in comparison with mechanical properties of the initial irradiated fluoropolymer. Thus it is possible to minimize or completely avoid the degradation of mechanical properties of the final grafted composites in comparison with the initial fluoropolymers by choosing appropriate reaction conditions. 

Choice of sensitizer is related to the base polymer properties. Besides triplet sensitizers, dyes(4, 5), metal salts(11, 12), and radical initiators(7, 11, 12) have been used in photografting. These sensitizers other than triplet sensitizers are, however, not capable of initiating surface photografting onto polyolefins. Although benzoin isopropyl ether has been used for photografting of polypropylene, the reaction conditions seem to be in favor of deep grafting(12). 

---