Graft copolymers solubility data

The photopolymerization of St with catalytic amount of 52 as the pho-toiniferter gave a benzene-soluble polymer that contains a styryl double bond and a DC group at the polymer chain ends. When this macromonomer-iniferter 54 was copolymerized with a second monomer in the presence of an azo initiator, the formation of a high molecular weight graft copolymer was confirmed by GPC data. The monomer iniferter 52 was also used for the preparation of photoresist polymers [189]. 

Oxazolines have been used in block and graft copolymerization. Addition of 2-methyl-OXL to living polyTHF yielded block copolymer l9). Mostly on the basis of solubility data the formation of block copolymers of 2-methyl-2-oxazoline and styrene oxide (initiation with I2) were claimed 20). 

Due to the low solubility of poly(4-vinyl pyridine) in THF, a block copolymer of 4-vinyl pyridine with styrene has been used (Mn = 13,500). Living polyTHF (Mn = 3,300) has been grafted with efficiencies higher than 95 %. About 20 % of the pyridine units were consumed, yielding a graft copolymer with 80% polyTHF. No further data on this product were reported. 

These data imply that all the sediment consists of microgels of graft copolymer. If a certain amount of polybutadiene were not grafted and not crosslinked, it would be insoluble in MEK and then appear when the ABS sample is dispersed in MEK. Although Gesner (2) detected soluble pure polybutadiene in ABS compounds, this might be the result of different preparation techniques. 

The formation of grafted copolymer is evidenced by a change in solubility, fractionation attempts, a second glass transition temperature, and gel permeation chromatography data. 

Figure 1. Solubility data of graft copolymers prepared with different levels of free radical initiator.

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