Synthesis of a bifunctional epoxy monomer containing anthracene moiety and properties of its cured polymer with phenol novolac

A new type of epoxy resin containing anthracene moiety in the backbone was synthesized and was confirmed by elemental analysis, infrared spectroscopy, and ¹H nuclear magnetic resonance spectroscopy. Thermal properties of its cured polymer with phenol novolac were examined by thermomechanical, dynamic mechanical, and thermogravimetric analyses. The cured polymer with phenol novolac showed higher glass transition temperature (T_g), lower thermal expansion, lower moisture absorption, and higher anaerobic char yield at 700°C than a cured polymer having a phenylene group in place of anthracene moiety. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 953–959, 1999     

Saccharomycodes ludwigii has seven chromosomes

Tetrad distributions for 108 different gene pairs in 1346 asci of 113 diploids heterozygous for various combinations of 24 genes in Saccharomycodes ludwigii were investigated. Tetratype tetrads occurred only rarely and the 24 genes tested were classified into seven linkage groups. Electrophoretic karyotypes of three independent strains of S'codes ludwigii showed seven bands of chromosome-sized DNA having molecular sizes of 0·8 to 2·3 Mb with strain-specific polymorphic chromosomal DNAs as determined based on their migration distances.     

Effect of molecular weight on rate of enthalpy relaxation of poly (methyl methacrylate) and its oligomers

The enthalpy relaxation process of methyl methacrylate oligomers and poly (methyl methacrylate) was analyzed by use of the excess enthalpy (ΔH_t), which was obtained from a differential scanning calorimetric measurement. The apparent relaxation time (τ_½) was estimated by the assumption of the single relaxation time response. The T_g of oligomers increased with an increase of molecular weight, and approached a constant value above 1 × 10⁴. The apparent relaxation time showed a similar molecular-weight dependency as T_g, and approached a constant value above 1 × 10⁴. It was expected that the molecular motion which caused the enthalpy relaxation was based on the segmental motion of main chains.     

Studies on synthetic-polymer plates with high surface energy. V. Diethylene glycol bis(allyl carbonate)–acrylic acid copolymer plate by vapor-phase transfer process

Synthetic-polymer plates with carboxyl group on their surface were prepared by a two-step copolymerization process transferring M₂ monomer via vapor phase. Diethylene glycol bis(allyl carbonate) (CR-39) was used as M₁ monomer, and acrylic acid was acid was used as M₂ monomer. The relations between the experimental conditions and the surface properties of the resulting plates were examined in the following terms: (1) composition of CR-39 prepolymer gel plate used and (2) concentration of benzoyl peroxide as the initiator. The plates had good water wettability and an excellent antifogging property.