Radiation curing and grafting of charge transfer complexes

Charge transfer (CT) complexes have been used in a number of radiation polymerisation processes including grafting and curing. The complexes studied include donor (D) monomers like vinyl ethers and vinyl acetate (VA) with acceptor (A) monomers such as maleic anhydride (MA). Both UV and EB have been utilised as radiation sources. The complexes are directly grafted to these substrates in the presence of radiation. The complexes yield novel copolymers when radiation cured with concurrent grafting improving the properties of the finished product. The term cure grafting has been proposed for this concurrent grafting process. Studies in basic photografting work to complement the cure grafting have been proposed. The role of solvent in grafting is discussed, particularly the effect of aromatics in photografting to naturally occurring trunk polymers like wool and cellulose. The effect of the double bond molar ratio (DBMR) of the DA components in grafting is examined. The ultraviolet (UV) conditions for gel formation during photografting, hence the importance of homopolymer yields in these processes is reported. A plausible mechanism to explain the results from this photografting work is proposed. The significance of these photografting studies in the related field of curing, especially in UV and ionising radiation (EB) systems, is discussed. EB curing and cure grafting of charge transfer (CT) monomer complexes is investigated. The EB results are compared with UV curing and cure grafting of the same complexes. The work has been extended to include EB/UV curing and cure grafting of thiolene systems. The significance of these results in the potential commercial application of these complexes is discussed. Variables affecting the UV/EB curing and cure grafting of thiolenes on cellulose have been studied. These include effect of varying the type of olefin, increasing the functionality of the thiol, use of acrylate monomers and oligomers in hybrid systems, altering the surface structure of the cellulose and finally the role of air in these processes particularly with EB. Photopolymerisation of the thiol-enes in bulk has also been investigated. The thesis content is based on the published work of 14 research papers over the course of the project

EB curing and cure grafting of novel CT monomer complexes : comparison with UV process and extention of the technique to thiol-ene systems

EB curing and cure grafting of charge transfer (CT) monomer complexes is discussed. The complexes studied involve representative donors (D) such as vinyl ethers and typical acceptors (A) including maleates, maleimides and acrylates also oligomers. The EB results are compared with UV curing and cure grafting of the same complexes. The work has been extended to include EB/UV curing and cure grafting of thiol-ene systems. The significance of these results in the potential commercial application of these complexes is discussed

Cure grafting - a complementary technique to preirradiation and simultaneous processes?

A novel radiation grafting process, termed cure grafting, based on curing of donor/acceptor (DA) monomers as charge transfer complexes initiated by UV or any ionising radiation source, is proposed. The system is complementary to the existing preirradiation and simultaneous radiation grafting methods. The advantages and disadvantages of cure grafting are summarised. Examples of cure grafting using representative DA monomers are described with cellulose as model substrate in the presence of UV or EB. A unique property of cure grafting is that the yield is known quantitatively prior to irradiation

Radiation curing of composites

The use of radiation curing in the synthesis of composites is discussed including the value of ultraviolet light (UV) versus electron beam (EB) as sources. The advantages and limitations of the UV process areexamined. The technique is briefly described in tenns of equipment, types of resins used including donor/acceptor monomers and specific fibres and fillers appropriate for the process. The significance of concurrent grafting on the fibres during curing of composites is discussed. Additives for enhancing rates of curing and grafting of the matrix resins are reported. Mechanisms to explain the observed polymerisation processes are described including spectroscopic studies. Emerging technologies including the future of nanocomposites are outlined. A unique Australian application of UV composites is discussed - the banknote

Effect of monomer structure on radiation grafting of charge transfer complexes to synthetic and naturally occurring polymers

Effect of monomer structure in photografting charge transfer (CT) complexes to typical substrates like wool, cellulose and polypropylene is reported. The importance of photoinitiators in these processes is examined. Maleic anhydride (MA) with triethylene glycol divinyl ether (DVE-3) is used as reference CT complex in this work. The additional monomers studied include the esters of MA as acceptors and vinyl acetate as donor. The role of solvent in these reactions is discussed, particularly the effect of aromatics in photografting to naturally occurring trunk polymers like wool and cellulose. The effect of the double bond molar ratio of the DA components in grafting is examined. The ultraviolet (UV) conditions for gel formation during photografting, hence the importance of homopolymer yields in these processes is reported. A plausible mechanism to explain the results from this photografting work is proposed. The significance of these photografting studies in the related field of curing, especially in UV and ionising radiation systems, is discussed

CT complexes in radiation polymerisation processes including grafting, curing and hydrogel formation

Parameters influencing the grafting of a typical charge transfer (CT) complex, maleic anhydride /triethylene glycol divinyl ether, to representative substrates, cellulose and polypropylene, initiated by UV and ionising radiation have been investigated. The variables studied include effect of solvent, role of donor involving the type of ether and the nature of the acceptor including the use of common monomers like methyl methacrylate. A novel application of this CT grafting work is reported involving hydrogel formation with subsequent controlled release of incorporated reagent