Stephen Neal Falling

Alternating Copolymerization of 3,4-Epoxy-1-Butene and Derivatives with Maleic Anhydride

Abstract 3,4-Epoxy-1-butene (I), prepared by the selective oxidation of butadiene, is an unusual difunctional monomer containing polymerizable vinyl and epoxy groups. As expected, free radical homopolymerization of I and its cyclic ketal derivatives was found to be very sluggish, as expected, for the allylic monomer structures. However, I was found to form alternating copolymers with maleic anhydride with both 1,2- and 1,5- enchainment observed. The structures of the alternating copolymers were observed to be solvent dependent with the in situ formation of cyclic ketals and their incorporation into the copolymers in polymerizations done in ketone solvents. Various cyclic ketal monomers derived from I readily formed alternating copoymers with maleic anhydride. Thermally activated self-crosslinking of these resins was observed.

STUDY OF THE PHOTOINITIATED CATIONIC POLYMERIZATION OF 3,4-EPOXY-1-BUTENE

The photopolymerization of 3,4-epoxy-1-butene (1) was investigated using Fourier transform real-time infrared spectroscopy (FT-RTIR). The effects of photoinitiator structure and concentration and light intensity on the photopolymerization were investigated. Compared to related epoxide monomers, 1 was shown to be more reactive and this was ascribed to stabilization of the growing cationic chain end by the double bond during the ring-opening polymerization. Epoxide 1 was also shown to be useful as a reactive diluent in the photopolymerization of multifunctional epoxides and was observed to accelerate the polymerization of less reactive epoxy monomers.

INVESTIGATION OF THE USE OF POLY(3,4-EPOXY-1-BUTENE) IN FREE RADICAL PHOTOPOLYMERIZATIONS

ABSTRACT The use of poly(3,4-epoxy-1-butene) (polyEPB) in photoinduced free radical polymerizations has been investigated. It was observed that the inclusion of polyEPB into these photopolymerizations has several beneficial effects. In combination with aromatic ketones, polyEPB functions as a hydrogen donor to form a highly effective photoinitiator for the polymerization of acrylate monomers. At the same time, polyEPB undergoes facile autoxidation that serves to mitigate inhibition effects due to oxygen during free radical photopolymerizations. PolyEPB is an effective chain transfer agent that tends to increase both the rate and conversion in photoinduced crosslinking polymerizations in which multifunctional monomers are employed. Lastly, polyEPB is a interesting matrix-modifying agent that becomes incorporated into the resin matrix during photopolymerization due to photoinduced grafting reactions.

PHOTOINITIATED CATIONIC POLYMERIZATION OF EPOXY MONOMERS IN THE PRESENCE OF POLY(3,4-EPOXY-1-BUTENE)

ABSTRACT Hydroxyl-terminated poly(3,4-epoxy-1-butene) (polyEPB) is an interesting and highly useful agent for the acceleration of the photoinitiated cationic ring-opening polymerization of epoxide monomers. Kinetic investigations using real-time infrared spectroscopy have shown that the observed acceleration of the polymerization is due to two independent mechanisms. Crosslinking polymerization of epoxide monomers is accelerated due to an activated monomer mechanism that results in facile chain transfer due to interaction of the terminal hydroxyl groups of polyEPB with the growing oxonium ion chain ends. A second mechanism involving participation of polyEPB in a free radical chain induced decomposition of the onium salt photoinitiator is mainly responsible for the observed acceleration in the rate of polymerization. A large number of polymer-bound carbocationic species are generated by this mechanism that are capable of initiating polymerization of the epoxide monomer.