Temperature profiles and weight loss in the thermal decomposition of large spherical wood particles

1993 ◽  
Vol 32 (9) ◽  
pp. 1811-1817 ◽  
Author(s):  
Rafael Bilbao ◽  
Angela Millera ◽  
Maria B. Murillo
Keyword(s):  
Thermal Decomposition ◽  
Weight Loss ◽  
Temperature Profiles ◽  
Wood Particles ◽  
Large Spherical

Gas formation in the thermal decomposition of large spherical wood particles

1997 ◽  
Vol 43 (1) ◽  
pp. 27-39 ◽  
Author(s):  
R. Bilbao ◽  
J. Arauzo ◽  
M.B. Murillo ◽  
M.L. Salvador
Keyword(s):  
Thermal Decomposition ◽  
Gas Formation ◽  
Wood Particles ◽  
Large Spherical

Angular and radial temperature profiles in the thermal decomposition of wood

1992 ◽  
Vol 200 ◽  
pp. 401-411
Author(s):  
Rafael Bilbao ◽  
María Benita Murillo ◽  
Angela Millera
Keyword(s):  
Thermal Decomposition ◽  
Temperature Profiles ◽  
Radial Temperature

Synthesis and thermal decomposition kinetics of poly(methyl methacrylate)-b-poly(styrene) block copolymers

2015 ◽  
Vol 30 (5) ◽  
pp. 691-706 ◽  
Author(s):  
Xinghua Guan ◽  
Xiaoyan Ma ◽  
Hualong Zhou ◽  
Fang Chen ◽  
Zhiguang Li
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Weight Loss ◽  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Terminal Group ◽  
Loss Ratio ◽  
Poly Methyl Methacrylate ◽  
Second Stage ◽  
Weight Loss Ratio

Two diblock copolymers of poly(methyl methacrylate)- block-poly(styrene) with chlorine as terminal group (PMMA- b-PS-Cl) were synthesized via two-step atom transfer radical polymerization. The structures of the block copolymers were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and gel permeation chromatography. Thermal properties including glass transition temperature ( Tg) and thermal stability were studied by differential scanning calorimetry and thermogravimetric analysis (TGA), respectively. The block copolymers of PMMA- b-PS-Cl exhibited two glass transitions, which were attributed to the Tgs of PMMA and PS segments, respectively. According to TGA, thermal decompositions of PMMA macro-initiator and PMMA- b-PS-Cl block copolymers had two stages. The weight loss ratio in the second stage was more significant than that in the first stage, which may be attributed to the separation of the halogen atom from the terminal group and the formation of a double bond. The breaking down of the backbone dominates in the second stage in which the weight loss ratio was more than 70%, represented the main stage of pyrolysis. It was found that the introduction of the PS chain remarkably enhanced the thermal stability of the copolymer, thus endowing the block copolymers high activation energy for thermal decomposition. On the other hand, the remaining two pyrolysis procedures further indicated that thermodynamic mechanism didn’t change due to the introduction of PS segments.

scholarly journals Thermal stability of polyurethane coating prepared by using diphenylolpropane

2020 ◽  
Vol 62 (4) ◽  
pp. 81-87
Author(s):  
Indira N. Bakirova ◽  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Weight Loss ◽  
Elevated Temperatures ◽  
Onset Temperature ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Groups ◽  
Polyurethane Coating ◽  
Urethane Group ◽  
Thermal Stability Of

Thermal stability of polyurethane varnish coating prepared by using diphenylolpropane, polyetherpolyol and polyisocyanate with an equimolar ratio of isocyanate and hydroxyl groups was assessed in the air. The polyurethane weight loss thermogram shows three temperature regions: I – (217-275)°С, II – (275-380)°С, and III – above 380°С. For interpreting thermogram of the polyurethane under study the model substances simulating the urethane groups of a polymer were synthesized. The substance containing the urethane group formed by phenolic hydroxyl of diphenylolpropane was shown to demonstrate relatively low thermal stability and gets broken down into isocyanate and bisphenol. Decomposition of the substance containing the urethane group formed by alcoholic hydroxyl occurs at the higher temperature. The data obtained allow interpreting the occurrence of thermal decomposition step I in TGA curve by structural changes in the blocks formed by diphenylolpropane and polyisocyanate being the least stable when exposed to elevated temperatures. The next step can be attributed to decomposition of more thermostable urethane groups formed by functional groups of oligooxypropylenetriol and polyisocyanate. Transition to the step III accompanied by severe sample weight loss due to decomposition of urethane groups is explained by thermal oxidation of oligoether units of polymer. Based on the data obtained the conclusion was made that the presence of urethane groups formed by phenolic hydroxyl of diphenylolpropane in polymer structure results in the decreased thermooxidative decomposition onset temperature of polymer. At the same time, a deceleration of thermooxidative processes due to the stabilizing effect of diphenylolpropane released at the beginning of thermal decomposition of polyurethane is observed in a high-temperature region. The proposed polyurethane coating is inferior to commercial counterparts in thermal decomposition onset temperature but superior to them in the temperature corresponding to a 50% polymer weight loss.

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