Synthesis and decomposition performance of a polymeric foaming agent containing a sulfonyl hydrazide moiety

A new monomer, methacryloyloxybis(benzenesulfonyl hydrazide) (MAOBSH) containing a foamable sulfonyl hydrazide functional group after decomposition by heating, was synthesized from 4,4′‐oxybis(benzenesulfonyl hydrazide) (OBSH) with methacryloyl chloride, and used to obtain poly(MAOBSH) as a polymeric foaming agent (PFA) in dry tetrahydrofuran at 70 °C using azobisisobutyronitrile as an initiator. The structures of the synthesized MAOBSH and poly(MAOBSH) were identified using Fourier transform infrared and ¹ H NMR spectroscopies. The decomposition temperature of poly(MAOBSH) was determined to be 245 °C and this temperature was decreased to around 160 °C by adding an activator such as surface‐treated urea to the polymer. The exothermic temperature and heat determined by the decomposition of the polymer were 256 °C and 287 J g^?1. The amount of gas evolution for poly(MAOBSH) measured at the decomposition temperature was 74 mL g^?1. Furthermore, polymers incorporating the PFA showed better skin and finer cell structure as well as better mechanical properties such as elongation and compression set than polymers with added OBSH due to the better compatibility of the developed PFA with polymers. © 2012 Society of Chemical Industry     

Effects of mechanical force on crystalline structure of electrospun poly(1‐butene) membranes

Fibrous poly(1‐butene) membranes were prepared from solutions using mixed solvents via electrospinning. The electrospun fibrous poly(1‐butene) membranes were stretched at elongations of 8, 16 and 24%, respectively. Scanning electron microscopy and stress–strain analysis showed that the deformation was elastic at an elongation of 8%, while plastic deformation occurred above 16%. The crystalline transformation induced by mechanical stretching was investigated using wide‐angle X‐ray diffraction. The poly(1‐butene) membrane stretched at 24% exhibited decreased diffraction intensity at 2θ = 11.8° and 18.3°, corresponding to the (200) and (213) crystalline reflections, indicating that crystalline transformation from metastable form II to either stable form I or I′ occurred due to mechanical stretching. Copyright © 2011 Society of Chemical Industry     

Modification of wheat gluten with citric acid to produce superabsorbent materials

Wheat gluten was reacted with citric acid to produce natural superabsorbent materials able to absorb up to 78 times its weight in water. The properties of the modified gluten samples were characterized using Fourier Transform Infra‐red (FTIR) spectroscopy, thermogravimetric analysis, and water uptake. The reaction between gluten and citric acid was examined for gluten : citric acid ratios of 0.38 : 1 to 0.75 : 1 at temperatures from 100 to 130°C. More citric acid reacted for samples containing higher citric acid concentrations and at higher temperatures. FTIR analyses indicated the presence of carboxylate groups on the modified gluten samples, which resulted in modified samples having higher water uptake values than neat gluten. The sample with a gluten:citric acid ratio of 0.5 : 1 and reaction temperature of 120°C had the largest water uptake value. Also, all modified gluten samples had lower thermal stability than neat gluten. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Modeling reaction kinetics of rigid polyurethane foaming process

A theoretical model was developed to simulate the polyurethane foaming process for a rigid foam. In the model, multiple ordinary differential equations were solved by MATLAB and the model was able to predict temperature profiles by inputting foam recipe information. This initial study on foam modeling focusses on reaction kinetic parameters that were fitted to experimental temperature data as a function of time. The modeling was able to accurately model temperature profiles of single‐polyol polyurethane formulations and was able to accurately predict temperature profiles of mixtures based on pure component kinetic parameters. A primary goal of this work is to expedite the ability to develop new foam formulations by simulation—especially for incorporation of new bio‐based polyols into formulations. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1131‐1138, 2013