Polymer grafting carboxylic acid groups

Actually these polyesters might also have had carboxylic acid end-groups, which would react even more readily with epoxy to form ester-linked graft copolymers. In several studies, the epoxy group was clearly reacted with polymers containing carboxylic acid groups, producing compatibility in this way [141, 144, 145, 150, 152, 153]. 

Fig. 14. Hyperbranched polymer grafts prepared on a mercaptoundecanoic acid (MUA) self assembled monolayer confined to a gold substrate. PAAM-c-PAA represents a random copolymer of poly(acrylamide) and poly(acrylic acid) prepared from the poly(acrylic acid) carboxylic acid groups and an amine [129]...

Interchain copolymer formation Copolymers of reactive polystyrene and polymers with amide, mercaptan, epoxy, hydroxy, anhydride or carboxylic acid groups, copolymer of polypropylene grafted with maleic anhydride and nylon-6, copolymer of polyolefines and polystyrene, copolymer of EVA grafted with methacrylates and grafted polystyrene... 

The grafting to method was used for the preparation of composites with the polymers containing reactive functional groups. One of the first examples of the grafting to approach was published by Fu et al in 2001. In this work, carboxylic acid groups on the nanotube surface were converted into acyl chlorides by refluxing the samples in thionyl chloride. Then the acyl chloride functionalised CNTs have been reacted with hydroxyl groups of dendritic PEG polymers via esterification reactions. 

As shown in Table 5.51, immiscible blends containing a functionalized polyolefin and a functionalized polyphenylene ether have been compatibilized through cross-linked or graft copolymer formation between carboxylic acid groups at multiple sites on one polymer and either cyclic ortho ester groups or epoxide groups at sites on another polymer. 

Acrylic acid-grafted PLA, titanium tetraisopropylate, and starch blends have been prepared by an in situ sol-gel and melt blending processes. The carboxylic acid groups of acrylic acid act as a coordination site for the titania phase to form a Ti-O-C chemical bond. This resulted in a nanoscale dispersion of Ti02 in the polymer matrix [100]. 

In both water-reducible coatings and wata-soluble polymers, the polymer chain, which is naturally hydrophobic, is altaed hydrophilic segments such as carboxylic acid groups, sulphonic acid groups, and tertiary amines are grafted onto the chain to confer a degree of water solubility. 

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