نتایج جستجو برای: thermal degradation
تعداد نتایج: 362694 فیلتر نتایج به سال:
The thermal degradation of polyethylene (PE) was carried out in the absence and presence ofcatalystes X-Zeolite and Silica-Alumina at different temperatures. The optimum PE/Catalysisratio was 0.25:0.05 g/g, which produced highest degradation value. PE and PE/Catalysis werecharacterized by thermogravimetric analysis. The thermal degradation properties of polymerhave been studied by Infrared spec...
the microstructure and thermal properties of the synthesized block copolymers and terpolymers via atom transfer radical polymerization (atrp) were studied. the mole fraction of the blocks and chain length of the pvac-b-pma block copolymers were estimated with 1h nmr spectroscopy.differential scanning calorimety measurement shows two different transitions at 36°c and 8°c assigned to pvac and pma...
Dimerization process is essential for producing copolymers. The features of dimerization process like thermal-oxidative degradation should be well known to reach maximum efficiency and a superior reactor design. Also, the degradation mechanism of biodegradable polymers is important during sterilization processes. Thermal-oxidative degradation of PGA, PLLA, and their binary copolymers was invest...
ionomers are generally described by copolymers having either acrylic or methacylic acid as one component and the other component is mostly either ethylene or styrene. the objective of this research was to study the thermal behaviour and stability of ionomers of styrene with some alkali metal acrylates. these materials have been synthesized by neutralization of the respective copolymer containin...
a series of polystyrene hybrid nanocomposites have been fabricated with varying amounts of tio2 viz., 0, 0.5 and 1 % w/w along with 3% ts by in-situ polymerization method. the influence of surface modified tio2 nanoparticles on the thermal properties of ps matrix was examined using thermogravimetry and differential scanning calorimetry. thermal characteristics of the polystyrene/ts/tio2 hybrid ...
The principal effects of mass degradation on polymer matrix composites (PMCs) are the decay of mechanical properties such as strength, elongation, and resilience. This degradation is a common problem of the PMCs under thermal cycling conditions. In this article, composite degradation was investigated by measurement of total mass loss (TML) using the Taguchi approach. Thermal cycling tests were ...
In this work, the role of comonomer content of 1-hexene-medium density polyethylene (MDPE) copolymer, synthesized using Phillips catalyst, on thermal behavior parameters such as: crystallization, melting temperature and thermal degradation was investigated in detail. The copolymer was fractionated to homogenous short-chain branching (SCB) fractions by "preparative temperature rising elution fra...
In this article, we investigate the thermal degradation of deoxyribonucleic acid (DNA). We find that under dry conditions, complete DNA degradation occurs at above 190°C. In addition, as the boiling temperature of water is pressure dependent, we have investigated the thermal degradation of the DNA in water for different applied partial pressures. This information is important for fundamental un...
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abstract this study is carried out to determine the chemical composition in the three vegetative stages of the haloxylon sp., degradation parameters, with adding naoh and ca(oh2 ). for this purpose, in may and october and january 2010 enough some haloxylon sp. of the ammary area was prepared. crude protein and ash percentage are decrease, neutral detergent fiber percentage with pragress stage ...
Degradation is a common problem for polymer matrix composites (PMCs) under low thermal cycling conditions. This paper investigates the effects of low thermal cycling on total mass loss (TML) and surface degradation of PMCs. Unnotched and open-hole specimens were weighed before and after low thermal cycling. The total mass loss and surface degradation of the specimens were studied over 250 cycle...
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