Melt spinning of high-strength fiber from low-molecular-weight polypropylene

2015 ◽  
Vol 56 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Qianchao Mao ◽  
Tom P. Wyatt ◽  
An-Ting Chien ◽  
Jinnan Chen ◽  
Donggang Yao
Keyword(s):  
Molecular Weight ◽  
Melt Spinning ◽  
High Strength ◽  
Low Molecular Weight ◽  
High Strength Fiber

High-Speed Melt Spinning of Sheath-Core Bicomponent Polyester Fibers: High and Low Molecular Weight Poly(ethylene Terephthalate) Systems

1997 ◽  
Vol 67 (9) ◽  
pp. 684-694 ◽  
Author(s):  
J. Radhakrishnan ◽  
Takeshi Kikutani ◽  
Norimasa Okui
Keyword(s):  
Molecular Weight ◽  
High Speed ◽  
Melt Spinning ◽  
Ethylene Terephthalate ◽  
Maxwell Model ◽  
Low Molecular Weight ◽  
Structural Development ◽  
Solidification Temperature ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Sheath-core bicomponent spinning of high molecular weight poly (ethylene terephthalate) (hmpet, IV = 1.02 dl/g) and low molecular weight pet (lmpet, IV = 0.65 dl/g) is done at a take-up velocity range of 1 to 7 km/min. The structures of the individual components in the as-spun bicomponent fibers are characterized. Orientation and orientation-induced crystallization of the hmpet component are enhanced, while those of the lmpet component are suppressed in comparison to corresponding single component spinning. Numerical simulation with the Newtonian model shows that elongational stress in the hmpet component is enhanced and that of the lmpet decreases during high-speed bicomponent spinning. The difference in elongational viscosity is the main factor influencing the mutual interaction between hmpet and lmpet, which in turn affect spinline dynamics, solidification temperature, and structural development in high-speed bicomponent spinning. Simulation with an upper-convected Maxwell model shows that considerable stress relaxation can occur in the lmpet component if the hmpet component solidifies before lmpet. A mechanism for structural development is also proposed, based on the simulation results and structural characterization data.

Synthesis and Application of a Modifier to Enhance General Properties of the Polar Wood

2011 ◽  
Vol 675-677 ◽  
pp. 399-402
Author(s):  
Yi Fei Jiang ◽  
Guo Feng Wu ◽  
Hao Zhang ◽  
Ping Qu ◽  
Jun Wen Pu
Keyword(s):  
Molecular Weight ◽  
Bending Strength ◽  
Treated Wood ◽  
High Strength ◽  
High Reactivity ◽  
Degree Of Crystallinity ◽  
Molar Ratio ◽  
Low Molecular Weight ◽  
Impregnation Method ◽  
Resin Impregnation

A preparation method of modifier with low molecular weight and high reactivity is presented. This modifier （called KFK in lab）can impregnate into polar wood along trachea from the ends with pressurized impregnation method. In the following heating and pressing processes of the polar wood, the KFK polymerizes, and it enhances stability and strength of the wood. It showed that the favorable conditions for synthetic reaction of the KFK are: molar ratio of U and F, 1:1; reaction temperature, 20°C; reaction time, 3 hours; dosage of ignition primer A: 5%. Results from test showed the degree of crystallinity tested by XRD were 30%, 32% in different dosage of the modifier. Utilizing a combination of low molecular weight resin impregnation and pressing resulted in a density increase of KFK resin-treated wood from 0.214 to 0.268g/cm3. At the same time, the Young’s modulus and bending strength increased from 1.407GPa to 1.759GPa and 64MPa to 74.5MPa, respectively. It can be concluded that the effective utilization of KFK resin impregnated in polar wood is a promising technique for the production of high-strength in the drying and pressing processing.

High strength distillery wastewater treatment by a PAC-MBR with low PAC dosage

2015 ◽  
Vol 73 (5) ◽  
pp. 1104-1111 ◽  
Author(s):  
Subhankar Basu ◽  
Ankita Kaushik ◽  
P. Saranya ◽  
Vidya S. Batra ◽  
Malini Balakrishnan
Keyword(s):  
Molecular Weight ◽  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Activated Carbons ◽  
Membrane Filter ◽  
High Strength ◽  
Low Molecular Weight ◽  
Treated Effluent ◽  
Cake Layer ◽  
Distillery Wastewater

Augmentation of membrane bioreactors (MBRs) with activated carbon is established to offer several operational advantages. This work investigates the influence of low dosing (2 g/L) of powdered activated carbons (PACs) with different characteristics on the performance of MBR treating high strength molasses distillery wastewater containing difficult-to-biodegrade recalcitrant components. Two MBRs, augmented with different PACs, were operated in parallel over a period of 240 days and their performance monitored in terms of biomass growth, reduction in chemical oxygen demand (COD), sludge properties like extracellular polymeric substances content, filterability, and morphology. Removal of organics and coloring matter by adsorption, biodegradation and membrane filtration was estimated. Although adsorptive removal of color and COD is influenced by the properties of the PAC used, the performance of the PAC-MBRs was independent of PAC properties. Both PACs preferentially adsorbed the low molecular weight components in distillery wastewater. Retention by the membrane filter with the secondary cake layer contributed to reduction in color and COD of treated effluent. The findings indicate that low dosing with PAC adsorbing low molecular weight organics has a limited role in PAC-MBR treating distillery wastewater.

Control on molecular weight reduction of poly(ε-caprolactone) during melt spinning — A way to produce high strength biodegradable fibers

2013 ◽  
Vol 33 (7) ◽  
pp. 4213-4220 ◽  
Author(s):  
Jit Pal ◽  
Nimesh Kankariya ◽  
Sunita Sanwaria ◽  
Bhanu Nandan ◽  
Rajiv K. Srivastava
Keyword(s):  
Molecular Weight ◽  
Weight Reduction ◽  
Melt Spinning ◽  
High Strength

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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