Eight xanthates were synthesized to induce living free radical polymerization of vinyl acetate. Four compounds, methyl (4‐methoxyphenoxy)carbonothioylsulfanyl acetate, methyl (methoxycarbonothioyl)sulfanyl acetate, methyl (ethoxycarbonothioyl)sulfanyl acetate and methyl (isopropoxycarbonothioyl)sulfanyl acetate were identified as suitable MADIX/RAFT agents, yielding low polydispersity (PDI < 1.2) poly(vinyl acetate) of molecular weights exceeding 5 × 104 g · mol−1. All suitable MADIX/RAFT agents exhibited extended periods of inhibition (0.3 h < tinh < 10 h) and moderate rate retardation. The ability of these compounds to control vinyl acetate polymerization can be correlated with the electron density on the central carbon atom of the xanthate. Electrospray ionization mass spectrometric analysis was performed to complete the investigation on the new MADIX/RAFT agents.

Catalytic chain transfer polymerization is a very efficient and versatile free-radical polymerization technique for the synthesis of functional macromonomers. The process is based on the ability of certain transition metal complexes, most notably of low-spin CoII complexes such as cobaloximes, to catalyse the chain transfer to monomer reaction. A brief overview is given of the applications and the mechanistic understanding of catalytic chain transfer polymerization.

Between 1986 and 1988 the annual incidence of invasive melanoma in the Hunter area of New South Wales, Australia, almost doubled to 52.5 per 100,000 in men and 42.9 per 100,000 in women. These rates have been maintained and are similar to those reported for 1987 in Queensland, Australia, which are the highest in the world. Most of the increase in incidence was in melanomas less than 1.50 mm in thickness, and adults of both sexes and all ages were affected. Thicker melanomas also increased in incidence but only in adults 45 years and older, and mainly in men. An analysis of health insurance data on treatment of skin lesions and data from a histopathology laboratory suggested that diagnosis and treatment of skin lesions generally in the Hunter area had increased almost 2-fold over this period. Advancement of the time of diagnosis and a real increase in incidence were likely explanations for some of the observed trends. Increasing diagnosis of a non-metastasising form of thin melanoma, consequent upon increasing removal of pigmented skin lesions by medical practitioners, may also explain some of the observed increase in the incidence of the disease. This possibility has important implications for proposed population screening programs, and methods are needed to distinguish such lesions, if they exist, from potentially fatal melanoma.

Pulsed-laser polymerization experiments were conducted on the copolymerization of 2-methylene 1,3-dioxepane (MDO) and methyl methacrylate (MMA) at 40 °C. Reactivity ratios, based on the terminal model, were determined from copolymer compositional analyses as r MDO = 0.057 and r MMA = 34.12. The average propagation rate coefficients, 〈k p〉, were determined for a number of feed compositions ranging from an MDO mole fraction of 0 to 0.916. It was not possible to obtain a 〈k p〉 value for the homopolymerization of MDO as the PLP experiment was compromised by high chain transfer rates to polymer and monomer. The data were fitted to a number of copolymerization models, viz. the terminal and the explicit and implicit penultimate unit models and the bootstrap solvent dependence model. It was found that the terminal and penultimate unit models for copolymerization could not adequately describe the experimental results. A fit to a bootstrap model was successful, but the values obtained indicated a very large, unprecedented, partitioning effect.