Poly solubility rates

Radiation Degradation and Film Solubility Rates of Poly(butene-l-sulfone)... 

The fabric is desized after the weaving operation and then passed through a heated water bath to remove all the size. The rate at which this operation can be accomplished depends to a great degree on solubility rate of the poly (vinyl alcohol). Difficulties encountered in completely removing the lubricating wax, usually tallow wax, has led to the development of several wax-free size compositions (303—311). The main component contained in these blends is PVA in combination with a small amount of a synthetic water-soluble lubricant. 

Ouano, A study of the dissolution rate of irradiated poly (methyl methacrylate), Polym. Eng. Sci. 18, 306 (1978) L.E. Stillwagon, Radiation degradation and film solubility rates of poly(butene 1 sulfone), Org. Coat. Plast. Chem. 43, 236 (1980). 

Unlike other water-soluble resins the poly(ethylene oxide)s may be injection moulded, extruded and calendered without difficulty. The viscosity is highly dependent on shear rate and to a lesser extent on temperature. Processing temperatures in the range 90-130°C may be used for polymers with an intrinsic viscosity of about 2.5. (The intrinsic viscosity is used as a measure of molecular weight.)... 

Fig. 22. Adhesion rating based on flexural sti engths of laminates of poly(styrene) with glass treated with various silane coupling agents vs. solubility parameter of the organo-functional group of the coupling agent. From ref. [117], by permission.

Initial work with poly (ortho esters) focused on norethindrone and the use of water-soluble excipients such as Na2C03, NaCl, and Na2S04 (27). As described by Fedors (28), the inclusion of such water-soluble salts leads to an osmotically driven water intake into the polymer. This water intake leads to polymer swelling with consequent release of the incorporated norethindrone. The effect of incorporated NaCl and Na2C03 on erosion rate as compared to the... 

With endogeneous pectic polysaccharides as substrates, the pectin methyhransferase activity was measured as radioactivity linked to oxalate-soluble polys x harides after extensive washing of microsomes with IM ethanolic NaCL Figure 2 shows that the rate of methylesterification of pectic substances was maximal on days 4 and 6 these maximum activities were observed within this period in at least five independent ejqjeriments. On the other hand, little activity was noted in young cells before day 2, and in old cells after day 9. In other words during the stationary phase the newly synthesised pectins remained unesterified because of the lack of pectin methyltransferase activity. 

Many acrylic acid copolymers are water-soluble but unlike poly(vinyl alcohol) they are not degraded by alkali. In fact they need alkali for effective desizing as they are more soluble at alkaline pH than in neutral solutions. They are sensitive to acidic media, which should not be used. Solubilisation occurs by the formation of sodium carboxylate groups from the anionic polyacid. The polyelectrolyte formed in this way is readily soluble and shows a rapid rate of dissolution. However, the presence of electrolytes such as magnesium or calcium salts from hard water can inhibit removal [191]. 

These representative aliphatic polyesters are often used in copolymerized form in various combinations, for example, poly(lactide-co-glycolide) (PLGA) [66-68] and poly(lactide-co-caprolactone) [69-73], to improve degradation rates, mechanical properties, processability, and solubility by reducing crystallinity. Other monomers such as 1,4-dioxepan-5-one (DXO) [74—76], 1,4-dioxane-2-one [77], and trimethylene carbonate (TMC) [28] (Fig. 2) have also been used as comonomers to improve the hydrophobicity of the aliphatic polyesters as well as their degradability and mechanical properties. 

In this case, a simple kinetic model could not be derived to explain all the experimental observations. Independently prepared hexadecyl trimethyl ammoniurn persulfate was found to be soluble in toluene/AN mixtures and to catalyze polymerization in this homogeneous system at approximately the same rate as that observed in the two phase system. This result implies that anion exchange at the interface (see below) must be essentially complete under these conditions. Factors which complicated further analysis of the mechanism included a) precipitation of poly(acrylonitri 1 e) during the polymerization ... 

Polymers of 4(5)-vinylimidazole and copolymers containing this monomer are usually studied with ethanol-buffer mixtures as solvent because of their insolubility in water. Overberger and Smith (82) found that poly(l-Me-5-vinylimidazole) was soluble in water. Negatively charged substrates with long apolar side chains were bound very strongly to this polymer. A rate enhancement of 106 over the monomeric analog, 1,5-dimethylimidazole, was observed. 

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