Advanced Materials Research Vols. 11-12

Abstract: In this study the vapour phase surface graft polymerization of acrylonitrile (AN) onto poly(ethylene terephthalate) (PET) film was conducted with benzoyl peroxide (BPO) as an initiator. Effects of reaction time and quantity of BPO on the polymerization were investigated. With the prolongation of reaction time, the graft polymerization took place rapidly at first, then slowed down, and leveled off. With the increase of BPO, the graft yield increased, then remained unchanged, and lastly began to decrease. The surface topography structure of the grafted PET film was observed by SEM. Grafted PET film was characterised by FTIR spectra, SEM photographs and contact angle measurement.

Abstract: Poly(ε-caprolactone) (PCL)-polystyrene (PS)star-block copolymer with a cross-linked microgel core were synthesized by the combination of atom transfer radical polymerization (ATRP) of St and lipase-catalyzed ring-opening polymerization (ROP) of ε-CL. The characterization of PCL-Br, PCL-PS-Br macroinitiator and PCL-PS Star-block copolymers was detected by GPC and 1H NMR. Results showed that the target star-block copolymers were successfully prepared.

Abstract: The inverse emulsion polymerization of dimethyldiallylammonium chloride (DMDAAC) with acrylamide (AM) was carried out using a redox system as initiator, petroleum ether as oil, and Span-85 and Tween-80 as emulsifiers. The cationic degree of the copolymer increased markedly when AM was fed into the system in batch. The effect of DMDAAC content on the intrinsic viscosity ([η]) and solubility of the copolymer, and the methods of feeding AM on the cationic degree and solubility of the copolymer was studied in this work. The cationic degree of 39.8% of the copolymer was achieved. When the molar ratio of AM to DMDAAC was 4.0, the copolymer with [η] of 10.02 dl/g and the dissolving time less than 15min was obtained. The structure of the copolymer was also characterized by IR spectrum.

Abstract: Environmentally benign adhesive was synthesized by dispersion copolymerization of styrene(St) and butyl acrylate (BA) in an ethanol medium with benzoyl peroxide (BPO) as the initiator and poly(vinylpyrrolidone) as the stabilizer in the presence of acrylic acid(AA) as the functional monomer. The effect of the concentration of stabilizer, initiator and functional monomer on the conversions, molecular weights and molecular weight distributions was investigated. The results show that the conversions almost keep invariable with the increasing of stabilizer concentration, but the molecular weights increase and molecular weight distributions decrease. Conversions increase with the increasing of initiator concentration, but the molecular weights and molecular weight distributions decrease. However with the increasing of functional monomer concentration, conversions and molecular weight distributions increase but the molecular weights decrease.

Abstract: Foaming of polystyrene (PS)/ supercritical dioxide system was studied in a batch process in order to achieve a better understanding of supercritical CO2 diffusion mechanism in polymer and foaming condition. In this study, PS sample was treated with CO2 at 5-30 MPa and 40-160°C, soaking times was about 30-120min.Using gravimetric method, the solubility of CO2 in PS was obtained. The study datum shows that the solubility of CO2 in PS increases with increment of pressures, but decreases with the increment of temperature. The sorbed amount of CO2 is from 0.02 % (7MPa,
160°C) to 0.11%
(30MPa,
40°C).The relation of glass transition temperature, volume expansion ratio, cells density of foaming with pressure and temperature also was discussed individually. The glass transition temperature of PS swelled with CO2 is 80°C-95°C, which is lower than the glass transition temperature of pure PS by 10°C-25°C. The cell density increases as the pressure increase, and it decrease as the temperature increase.

Abstract: Using of rubber non-rotating drill pipe protectors is one of the most important technology measures to reduce the casing wear and rotary torque of drill pipe in case of drilling deep well, ultradeep well, extended reach well and horizontal well. This paper presents the operating principle of protectors, and investigates the effect on contact pressure with the using of protectors by finite element analysis (FEA). The results give out the theoretical foundation of reducing the casing wear and rotary torque of drill pipe by using rubber non-rotating drill pipe protectors.