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The effects of dibutyltin dilaurate (DBTL) and epoxidized soya bean oil (EBO) on the dehydrochlorination reaction of chlorinated natural rubber (CNR) from latex were studied by the measurement of the HCl evolving rate during the thermal degradation of CNR and by the determination of the amounts of cyclic conjugated dienes that formed on the CNR molecular chains. During the early stage of the thermal degradation of CNR at 150°C, HCl was eliminated, and the cyclic conjugated dienes formed on the CNR molecular chains. Under the effects of DBTL and EBO, the HCl evolving rates during the early stage of the thermal degradation of CNR were reduced, whereas the amounts of cyclic conjugated dienes formed on the CNR molecular chains were increased. Under the effects of mixtures from the compounding of DBTL with barium stearate or 2,2′‐methylene‐bis(4‐methyl‐6‐tert‐butyl‐phenol) as well as the compounding of EBO with 2,2′‐methylene‐bis(4‐methyl‐6‐tert‐butyl‐phenol), not only the HCl evolving rate from CNR but also the formation of cyclic conjugated dienes decreased, and this indicated that the compounded mixtures had synergistic functions against the thermal degradation of CNR. However, the mixture from the compounding of EBO with barium stearate had no synergistic effect on increasing the thermal stability of CNR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1986–1991, 2006

The effects of stearates on the dehydrochlorination (DHC) reaction of chlorinated natural rubber (CNR) from latex were studied by the measurement of the HCl evolving rate during the early stage of the thermal degradation of CNR and by the determination of the amounts of cyclic conjugated dienes formed on the CNR molecular chains. During the early stage of the thermal degradation of CNR at 150°C, HCl was eliminated from the CNR molecular chains, and the cyclic conjugated dienes were formed on the CNR molecular chains. Under the effects of barium stearate, lead stearate, cadmium stearate, and calcium stearate, the HCl evolving rates of CNR were reduced, whereas the amounts of cyclic conjugated dienes that formed on the CNR molecular chains were increased. When zinc stearate was added, because of the formation of ZnCl2, which was an active catalyst of the DHC reaction of CNR, both the HCl evolving rate from CNR and the formation of cyclic conjugated dienes were increased. The results indicate that the addition of stearates can reduce the thermal stability of CNR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1981–1985, 2006

The thermooxidative degradation of methyl methacrylate-graft-natural rubber (MG) at different heating rates (B) has been studied with thermogravimetric analysis in an air environment. The results indicate that the thermooxidative degradation of MG in air is a one-step reaction. The degradation temperatures increase with B. The initial degradation temperature (To) is 0.697B + 350.7; the temperature at the maximum degradation rate, that is, the peak temperature on a differential thermogravimetry curve (Tp), is 0.755B + 368.8; and the final degradation temperature (Tf) is 1.016B + 497.4. The degradation rates at Tp and Tf are not affected by B, and their average values are 46.7 and 99.7%, respectively. The maximum thermooxidative degradation reaction rate, that is, the peak height on a differential thermogravimetry curve (Rp), increases with B. The relationship between B and Rp is Rp = 2.12B + 7.28. The thermooxidative degradation kinetic parameters are calculated with the Doyle model. The reaction energy (E) and frequency factor (A) change with an increasing reaction degree, and the variational trends of the two kinetic parameters are similar. The values of E and A increase remarkably during the initial stage of the reaction, then keep relevantly steady, and finally reach a peak during the last stage. The velocity constants of the thermooxidative degradation vary with the reaction degree and increase with the reaction temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1227–1232, 2003

The thermal degradation kinetics of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(HB–HV)] under nitrogen was studied by thermogravimetry (TG). The results show that the thermal degradation temperatures (To, Tp, and Tf) increased with an increasing heating rate (B). Poly(HB–HV) was thermally more stable than PHB because its thermal degradation temperatures, To(0), Tp(0), and Tf(0)—determined by extrapolation to B = 0°C/min—increased by 13°C–15°C over those of PHB. The thermal degradation mechanism of PHB and poly(HB–HV) under nitrogen were investigated with TG–FTIR and Py–GC/MS. The results show that the degradation products of PHB are mainly propene, 2-butenoic acid, propenyl-2-butenoate and butyric-2-butenoate; whereas, those of poly(HB–HV) are mainly propene, 2-butenoic acid, 2-pentenoic acid, propenyl-2-butenoate, propenyl-2-pentenoate, butyric-2-butenoate, pentanoic-2-pentenoate, and CO2. The degradation is probably initiated from the chain scission of the ester linkage. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1530–1536, 2003

The thermal degradation of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-HV)] was studied using thermogravimetry (TG). In the thermal degradation of PHB, the temperature at the onset of weight loss (To) was derived by To = 0.97B + 259, where B represents the heating rate (°C/min). The temperature at which the weight loss rate was maximum (Tp) was Tp = 1.07B + 273, and the final temperature (Tf) at which degradation was completed was Tf = 1.10B + 280. The percentage of the weight loss at temperature Tp (Cp) was 69 ± 1% whereas the percentage of the weight loss at temperature Tf (Cf) was 96 ± 1%. In the thermal degradation of P(HB-HV) (7:3), To = 0.98B + 262, Tp = 1.00B + 278, and Tf = 1.12B + 285. The values of Cp and Cf were 62 ± 7 and 93 ± 1%, respectively. The derivative thermogravimetric (DTG) curves of PHB confirmed only one weight loss step change because the polymer mainly consisted of the HB monomer only. The DTG curves of P(HB-HV), however, suggested multiple weight loss step changes; this was probably due to the different evaporation rates of the two monomers. The incorporation of 10 and 30 mol % of the HV component into the polyester increased the various thermal temperatures (To, Tp, andTf) by 7–12°C (measured at B = 20°C/min). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2237–2244, 2001

The thermooxidative degradation of poly (vinyl alcohol)/silica (PVA/SiO2) nanocomposite prepared with self-assembly monolayer (SAM) technique is investigated by using a thermogravimetry (TG) and Fourier transform infrared spectroscopy coupled thermogravimetry (FTIR/TG). The results show that although the thermooxidative degradation process of prepared nanocomposite is similar to that of the pure PVA, its thermooxidative stability has been greatly improved.