Studies on Melt Spinning. I. Effect of Molecular Structure and Molecular Weight Distribution on Elongational Viscosity

1972 ◽  
Vol 16 (3) ◽  
pp. 447-472 ◽  
Author(s):  
Chang Dae Han ◽  
Ronald R. Lamonte
2013 ◽  
Vol 850-851 ◽  
pp. 70-73
Author(s):  
Hua Wang ◽  
Hao Dong Song ◽  
En Guang Zou ◽  
Teng Jie Ge ◽  
Hong Fang

The performance of JHMGC100S, a kind of HDPE for pipe, was studied, and the comparison with other typical PE100 resin in China and abroad was also did. The results show that: the impact strength of JHMGC100S was higher than other samples, and the bending strength was almost the same; the molecular weight distribution was obvious bimodal; the processability of JHMGC100S was good, and the hydrostatic strength of the pipe which was produced by JHMGC100S fulfilled the rule in GB/T 15558.1-2003.


1985 ◽  
Vol 5 (2) ◽  
pp. 95-124 ◽  
Author(s):  
Qingrong Fan ◽  
Duanfu Xu ◽  
Delu Zhao ◽  
Renyuan Qian

Abstract A basic study of melt spinning of polypropylene is reported. This study is aimed at developing a new technology for the manufacture of fine denier polypropylene fibers for clothing end uses. It was found that the molecular weight of the polypropylene resin has-a key influence on structure development in the fiber spinline. By aiming at achieving a smectic structure of the as-spun fiber through a controlled degradation of polypropylene, we can spin fine denier good quality polypropylene fibers at temperatures below 280°C and speeds up to 2000 meters/minute.


2003 ◽  
Vol 76 (5) ◽  
pp. 1057-1073 ◽  
Author(s):  
Susmita Bhattacharjee ◽  
Harald Bender ◽  
Dilip Padliya

Abstract EPDM is produced by different polymerization processes. Therefore, careful engineering of polymer micro- and macro- structures is necessary to achieve desired performance characteristics. This review highlights the process capability of the EPDM slurry technology to tailor and control the molecular structural design. The catalyst and the polymerization technology produce EPDMs with a wide spectrum of chemical composition and Mooney viscosity. The relatively narrow molecular weight distribution of the polymers has been designed to offer the best combination of processing and physical properties. A unique technology for incorporation of long chain branching in the polymer has been developed. This highly selective catalyst technology controls the degree of branching and molecular weight distribution without any side reaction, while offering the flexibility to vary polymer composition and molecular weight. The EPDMs made with the modified molecular structure have a good balance of processing and performance characteristics.


2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 


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