Dataset Information

A Complexed Initiating System AlCl3·Phenetole/TiCl4·H2O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene.

ABSTRACT: A complexed initiating system AlCl3·phenetole/TiCl4·H2O was prepared by simply compounding AlCl3/phenetole and TiCl4/H2O and used for cationic polymerization of isobutylene. It was found AlCl3·phenetole/TiCl4·H2O exhibited activities 1.2-3 times higher than those of AlCl3/phenetole, and more than an order of magnitude higher than those of TiCl4/H2O, which indicated a notable synergistic effect produced in the complexed system. In addition, due to the higher activity of AlCl3·phenetole/TiCl4·H2O, lower coinitiator concentration and polymerization temperature, as well as higher monomer concentration were more favored for this complexed initiating system to produce polyisobutylene (PIB) with reasonable molecular weight (Mw) and molecular weight distribution (MWD). Furthermore, high molecular weight polyisobutylene (HPIB) with Mw = 1-3 × 105 g·mol-1 could be successfully produced by the complexed catalyst system at Tp = -60 to -40 °C. As a whole, the high activity as well as the simple preparation procedures of the complexed initiating system offer us a unique approach for the production of HPIB with improved efficiency.

SUBMITTER: Jin Y

PROVIDER: S-EPMC6960821 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

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A Complexed Initiating System AlCl3·Phenetole/TiCl4·H2O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene.

Jin Yulong Y Chen Liang L Guo Xing X Xu Linfeng L Zhu Zhihua Z Liu Zhen Z Cheng Ruihua R Liu Boping B

Polymers 20191217 12

A complexed initiating system AlCl3·phenetole/TiCl4·H2O was prepared by simply compounding AlCl3/phenetole and TiCl4/H2O and used for cationic polymerization of isobutylene. It was found AlCl3·phenetole/TiCl4·H2O exhibited activities 1.2-3 times higher than those of AlCl3/phenetole, and more than an order of magnitude higher than those of TiCl4/H2O, which indicated ...[more]

PMID: 31861159

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Project description:Background Recent data suggests clinically significant weight gain among non-pregnant HIV-positive adults after starting dolutegravir-based ART (DTG). Excess or insufficient weight gain in pregnancy could adversely impact pregnancy outcomes, but data for pregnant women receiving DTG are limited. Methods The Tsepamo Study captured data at delivery sites in Botswana from 2014 to 2019. HIV testing, HIV treatment information, and weight measurements during antenatal care were abstracted from the maternity obstetric record at delivery. HIV-positive women initiating DTG or efavirenz-based ART (EFV) between conception and 17 weeks gestation and HIV-uninfected women first presenting for antenatal care before 17 weeks gestation were included. We evaluated weekly weight gain, total 18-week weight gain, excess weight gain (>0.59 kg/week), insufficient weight gain (<0.18 kg/week), and weight loss between 18±2 and 36±2 weeks gestation, adjusting for demographic and clinical variables. Findings Baseline characteristics were similar by exposure group, including pre-pregnancy and early pregnancy weight. Compared with EFV, mean weekly weight gain between 18 and 36 weeks gestation was 0.05 (95% CI 0.03, 0.07) kg/week higher for women initiating DTG and 0.12 (0.10, 0.14) kg/week higher for HIV-uninfected women. Mean 18-week weight gain was 1.05 (95% CI 0.61, 1.49) kg higher for women initiating DTG and 2.31 (1.85, 2.77) kg higher for HIV-uninfected women, compared with EFV. Women initiating DTG were more likely to gain excess weight but less likely to gain insufficient weight or lose weight than women initiating EFV. Interpretation Women initiating DTG compared with EFV during pregnancy gained more weight between 18 and 36 weeks gestation. Neither group gained as much weight as HIV-uninfected women. Initiating DTG compared with EFV during pregnancy could increase the risk of excess weight gain but decrease the risk of insufficient weight gain and weight loss, which could have positive and negative consequences in pregnancy. Our findings are consistent with prior studies in non-pregnant adults.

Dataset Information

A Complexed Initiating System AlCl3·Phenetole/TiCl4·H2O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene.

Publications

A Complexed Initiating System AlCl<sub>3</sub>·Phenetole/TiCl<sub>4</sub>·H<sub>2</sub>O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene.

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