Pilled Polymers

Synthetic fiber producers have attempted to minimise the tendency for pilling by several methods, one of which is to reduce polymer molecular weight. The resulting lower strength fiber would break away from the fabric surface more readily. Another method for reducing pilling is to notch or etch the fiber surface either before or after incorporation in fabric form. 

Similar to the work described by Spohn et al. [34], a trienzyme sensor was developed recently for the determination of branched-chain amino acids (L-valine, L-leucine, and L-isoleucine). Leucine dehydrogenase, NADH oxidase, and peroxidase were coimmobilized covalently on tresylate-hydrophylic vinyl polymer beads and packed into a transparent PILL tube (20 cm X 1.0 id), which was used as flow cell. The sensor was free of interferences from protein and NH4+ and it was stable for 2 weeks. The sensor system was applied to the determination of branched-chain amino acids in plasma with recoveries ranging from 98 to 100% [36],... 

Many other cyclic ethers have been polymerized using cationic polymerization. Ethylene oxide (also called oxirane) polymerizes forming poly(ethylene oxide) (PEO) (structure 5.24) in the presence of acids such as sulfuric acid, producing a wide range of chain-sized polymers sold under various trade names including Carbowax and Poly ox. PEO is also used in cosmetics and pharmaceuticals (as water-soluble pill coatings and capsules). 

Fig. 3 Aggregation numbers Z as a function of the degree of polymerization of the insoluble block for uncharged block copolymers. Open symbols correspond to different diblock-, triblock-, graft- and star polymers. Pilled symbols are low molecular weight...

Volksen W (1994) Condensation polyimides synthesis, solution behavior, and imidi-zation characteristics. In Hergenrother PM (ed) Advances in polymer science Vol 117 High performance polymers. Springer, Berlin Heidelberg New York, pill... 

J. Pilling. 2006. Carbon fibers, carbon-polymer composites and carbon-carbon composites. http //www. mse.mtu.edu/ drjohn/my4150/classl4/classl4.html... 

Phenomenology of the thermal decomposition, 765 Phonon model, 646 Photochemical degradation, 779 Photo-doping, 341 Photooxidation, 781, 783 Physical ageing, 438 Physical constants of solvents, 904 Physical data of simple gases, 657, 658 Physical properties of polymers, 920 Physical quantity, 52 Pilling, 881 tester, 881... 

Borst CL, Gill WN, Gutmann RJ. Chemical-Mechanical Polishing of Low Dielectric Constant Polymers and Organosilicate Glasses. Kluwer Academic Publishers 2002. pill. 

Within the family of cycloolefin co-polymers, the most important from a material properties standpoint, are the ethylene/norbornene co-polymers. These co-polymers, dubbed COC for cycloolefin co-polymers, are produced by Ticona and Mitsui under the tradenames Topas and Apel , respectively. An overview of properties and applications (for example, blisters for pills) can be found on Ticona s Topas homepage.607 Detailed ethylene/norbornene copolymerization studies with different 4/-symmetric and ansa-Cp-amido catalysts, with listing of co-polymerization parameters, have been published.608 611 NB is inserted exclusively in the cis-2,3-exo-modc (Scheme 25), and most of the metallocene catalysts tend to produce alternating co-polymers,609 612 due to the low reactivity of the M-NB intermediate toward further NB insertion. This mode of NB insertion prevents f3-H transfer, and thus ethylene/ norbornene co-polymers have increasing molecular masses at increasing NB content.611... 

Some acid-sensitive drugs can be protected by the way they are formulated. For example, it is possible to coat pills with an acid-resistant polymer which protects the drug from the acids in the stomach. The polymer is designed to be removed under the slightly alkaline conditions of the large intestine. Unfortunately, absorption in the large intestine is not so efficient as the small intestine and so the applications are limited. 

WO 99/14245 03/1999 Leupin et al.l Procter Gamble Laundry detergent compositions containing cellulosic-based polymers to improve fabric appearance and integrity Laundering of fabric/textiles with the additive leads to overall improvements in fabric appearance, pill/fuzz reduction, antifading properties, improved abrasion resistance, and enhanced softening... 

Neri C, Constanzi S, Farris R, Malatesta V (1991) In Patsis AV (ed) 13th Intern. Confer, on stabilization and degradation of polymers, 22-24 May 1991. Luzern, Proc pill... 

Figure 1.4 Modern materials in a variety of applications. A, Specialized steels in bicycles synthetic polymers in clothing and helmets. B, High-tension polymers in synthetic hip joints. C, Medicinal agents in pills. D, Liquid crystal displays in electronic devices.

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