Diisocyanate Divinyl

Polyvinyl alcohols may be applied as such or in crosslinked form [90]. Crosslinkers can be aldehydes (e.g., formaldehyde, acetaldehyde, glyoxal, glutaraldehyde), to form acetals, maleic acid or oxalic acid to form cross-linked ester bridges, or others (e.g., dimethylurea, polyacrolein, diisocyanate, divinyl sulfonate) [89,91]. 

Hydroxyl containing polymers may be cross-linked with diisocyanates. Fordyce and Ferry cross-linked styrene-maleic anhydride copolymers through the action of glycols. The copolymerization of divinyl with vinyl monomers may be looked upon as a method of cross-linking chain polymers. The cross-linkages are introduced simultaneously with the growth of the linear polymer chains, rather than afterwards, but this difference is secondary. 

Oil-Based SINs. The SINs produced were based on a castor oil polyester-urethane and styrene crosslinked with 1 mole percent of technical grade (55%) divinyl benzene (DVB) (7). This structure may be written poly[(castor oil, sebacic acid, TDI)-SIN-(Styfene, DVB)], poly[(CO,SA,TDI)-SIN-(S,DVB)]. Benzoyl peroxide (BP) (0.48%) was used as the free radical initiator for the styrene and 1,4-tolylene-diisocyanate (TDI) was used as the crosslinker for the polyester prepolymer. A 500 ml resin kettle equipped with a N inlet, condenser, thermometer, and high torque stirrer was used as the polymerization reactor. 

For use in plastics, this might require chain extension with diisocyanates, bisoxazolines, carbodiimides, bis(an-hydrides), and such. One use of the oligomers would be to form polyurethanes by reaction with isocyanates. The use of acid chlorides can be avoided if the polymers are made by ester exchange or made enzymatically, with compounds such as divinyl adipate. Poly(butylene sebacate) with a molecular weight of 46,400 has been made has been made from bis(2,2,2-trifluoroethyl)sebacate and 1,4-butane diol.150 One polyester with a molecular weight of 24,000 has been made by ester exchange from isosorbide and a... 

Di-A -vinylformylureas. A third option to prepare divinyl functional oligomers using NVF is through 1 1 reaction of NVF with a diisocyanate, such as isophoronediisocyanate, followed by reaction of the second isocyanate with a diol. As discussed earlier (2), the low reactivity and poor stability of the isocyanate adducts makes this option impractical. 

Scheme 6. Synthesis of Divinyl Resins Using Diisocyanate Linkers O...

---