Miscibility of components was assessed from glass transition temperature and is limited by the amount of PEA in the blend and by the content of c-caprolactam structural units in PEA. The effects of the content and type of PEA on their thermal stability and notched
impact strength were also investigated. The impact A769662 strength of the PVC blends reaches its maximum at an equimolar lactam to lactone units ratio in PEA; it decreases with increasing content of PEA in the blend. An admixture of a small amount of poly(epsilon-caprolactam) as a compatibilizer made it possible to prepare PEA-rich PVC blends, exhibiting twice as high notch impact strength, as compared to pure PVC. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 826-833, 2009″
“The degree and depth of curing due to photopolymerization in a commercial dental resin
have been studied using photothermal radiometry. The sample consisted of a thick layer of resin on which a thin metallic gold layer was deposited, thus guaranteeing full opacity. Purely thermal-wave inverse problem techniques without the interference of optical profiles were used. Thermal depth profiles were obtained by heating the gold coating with a modulated laser beam and by performing a frequency scan. Prior to each frequency scan, photopolymerization was induced using a high power blue light emitted diode (LED). Due to the highly light dispersive nature JPH203 solubility dmso of dental resins, the polymerization process depends strongly on
optical absorption of the blue light, thereby inducing a depth dependent thermal diffusivity profile in the sample. A robust depth profilometric method for reconstructing the thermal diffusivity depth dependence on degree and depth of polymerization has been developed. The thermal diffusivity depth profile was linked to the polymerization kinetics.”
“The modeling of thermal decomposition process of ten natural fibers commonly used in polymer composite industry was performed by assuming a global model occurring within the entire degradation range with consideration of fiber LY2157299 inhibitor as one pseudocomponent. Malek method with activation energy values previously obtained was applied to the modeling process. Careful calculation and evaluation indicated that, within an acceptable error limit of 5%, RO(n > 1) model can be used to describe the degradation process of most selected fibers well. The other kinetic parameters used include activation energy range of 160-170 kJ/mol; parameter n in RO(n > 1) = (1 – alpha)” of 3-4; and In A between 35 and 42 In s(-1). Some condition limitations of the obtained model were also discussed. The model has practical significance in predicting fiber weight loss when the fiber is used in combination with engineering thermoplastics. (C) 2009 Wiley Periodicals, Inc.