A series of polyurethanes from polyols derived from soybean, corn, safflower, sunflower, peanut, olive, canola, and castor oil were prepared, and their thermal stability in air and nitrogen assessed by thermogravimetric analysis, FTIR, and GC/MS. Oil-based polyurethanes generally had better initial thermal stability (below 10% weight loss) in air than the polypropylene oxide-based polyurethane, while the latter was more stable in nitrogen at the initial stage of degradation. If weight loss at a higher conversion is taken as the criterion of stability, then oil polyurethanes have better thermal stability both in air and in nitrogen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1723–1734, 2000

Thermal stability of polyurethanes based on vegetable oils

Pyrolysis of virgin and waste polypropylene and its mixtures with waste polyethylene and polystyrene

Basic study on a continuous flow reactor for thermal degradation of polymers

Effect of pressure on thermal degradation of polyethylene

A highly pure mixture of carbon and silica was obtained on pyrolysis rice husk leached with acid at high temperature in a nonoxidizing atmosphere. The product was suitable for use as a starting material in the the manufacture of silicon nitride powder. The effect of treatment including the kind and concentration of acid and the pyrolysis temperature on the constituents of the specimen was presented. Kinetic tests on pyrolysis of rice husk in a nitrogen atmosphere were carried out with a thermal gravimetric analysis (TGA) technique at heating rates 2, 3, and 5 K/min. The results indicated that thermal degradation of rice husk consisted of two distinct pyrolysis stages. The corresponding kinetic parameters including the activation energy were determined. A reasonable pyrolysis mechanism was proposed, which agreed satisfactorily with the experimental results.

Pyrolysis Kinetics of Acid-Leached Rice Husk

Various methods of thermogravimetric analysis were compared in case of polystyrene degradation. The reaction order, the activation energy and the preexponential factor were evaluated from common TG curves experimentally obtained. In most cases a 5-mg sample of polystyrene with 110,000 molecular weight was decomposed at heating rate of 10°C/min. The reaction was found under this experimental condition to be of first order with activation energy of 61.0 kcal/mole, though there were slight differences depending on the analytical methods used.

Comparative study of various methods for thermogravimetric analysis of polystyrene degradation

The new chiral monomer 3-oxobornyl methacrylate (OBMA) was synthesized from (+)-camphor. Homopolymerization of OBMA and copolymerization of OBMA with styrene were carried out in benzene in the presence of AIBN. The effect of concentration, solvent, temperature, and reaction time on the copolymerization were investigated. It was found that the absolute value of the specific rotation of poly(OBMA-co-St) increased by increasing the OBMA unit content. A small deviation from linearity was observed, which suggests that asymmetry is not introduced into the copolymer main chain. Temperature and solvent effects on the specific rotation of the chiral polymers were investigated. The results suggest that chiral polymers contain no helix conformation. Inspecting the spectra of optical rotatory dispersion and circular dichroism, we found that the chiral polymers exhibit a strong negative Cotton Effect around 310 nm.

Jenn Hwa Wang

Papers

Comparative study of various methods for thermogravimetric analysis of polystyrene degradation

Synthesis and polymerization of 3-oxobornyl methacrylate