Poly acid content

In a partially crystalline homopolymer, nylon 6, property enhancement has been achieved by blending with a poly(ethylene-co-acrylic acid) or its salt form ionomer [24]. Both additives proved to be effective impact modifiers for nylon 6. For the blends of the acid copolymer with nylon 6, maximum impact performance was obtained by addition of about 10 wt% of the modifier and the impact strength was further enhanced by increasing the acrylic acid content from 3.5 to 6%. However, blends prepared using the salt form ionomer (Sur-lyn 9950-Zn salt) instead of the acid, led to the highest impact strength, with the least reduction in tensile... 

Using this two-stage method and acetic acid as substrate, with culture volumes of 4 1 and 12.8 1, respectively, 857 ml of culture broth was harvested per hour containing a biomass concentration of 39 g l1 with a poly(3HB) content of 62%. The resulting productivity was 1.23 g 1 1 h 1 (Table 5). 

Studies on morphology and conclusions about observed levels of proton conductivity have also been carried out on PEMs other than Nafion and sulfonated poly(ether ketone). These include studies in which phenomenological examinations of relationships between conductivity and observed microstructure were carried out upon polymer systems where acid content was varied but the basic chemical structure was kept constant. In addition, other systems allowed... 

Postsulfonation of polymers to form PEMs can lead to undesirable side reactions and may be hard to control on a repeatable basis. Synthesis of sulfonated macromolecules for use in PEMs by the direct reaction of sulfonated comonomers has gained attention as a rigorous method of controlling the chemical structure, acid content, and even molecular weight of these materials. While more challenging synthetically than postsulfonation, the control of the chemical nature of the polymer afforded by direct copolymerization of sulfonated monomers and the repeatability of the reactions allows researchers to gain a more systematic understanding of these materials properties. Sulfonated poly(arylene ether)s, sulfonated poly-(imide)s, and sulfonated poly(styrene) derivatives have been the most prevalent of the directly copolymerized materials. 

Figure 10. Proton conductivity diffusion coefficient (mobility) and self-diffusion coefficient of phosphorus for poly-(diallyldimethylammonium-dihydrogenphosphate)—phosphoric acid ((PAMA+H2P04 ) nH3P04), as a function of the phosphoric acid content. Note that the ratio DJDp remains almost constant (see text).

Bionolle is an aliphatic polyester as shown in Fig. 2. We have two grades for Bionolle poly(butylene succinate) (PBS) and poly(butylene succinate/adipate) (PBSA), the copolymer of 1,4-butandiol and succinic acid/adipic acid. We call PBS the 1000 series, and PBSA the 3000 series. PBSA with higher adipic acid content is the 5000 series. 

Deters (14) vibromilled a blend of cellulose and cellulose triacetate. The acetic acid content of cellulose acetate decreased with grinding time (40 h) while that of the cellulose increased, suggesting the formation of a block or graft copolymer or of an esterification reaction by acetic acid developed by mechanical reaction. Baramboim (/5) dissolved separately in CO polystyrene, poly(methyl methacrylate), and poly(vinyl acetate). After mixing equal volumes of solutions of equivalent polymer concentration, the solvent was evaporated at 50° C under vacuum and the resultant product ball-milled. The examination of the ball-milled products showed the formation of free radicals which copolymerized. 

There are no accurate determinations of the overall contributions of peptide components to the compositions of HS and of SOM. The difficulties arise from the problems of separating these from other components of the SOM mixtures. Use of DMSO + 1% 12M HC1 and XAD-8 resin [(poly)methylmethacrylate] technology enabled Appelqvist et al. (1996) to decrease the amino acid content of a HA by 23%, and the decrease was uniform for the different amino acid groupings. This still left considerable amounts of peptide material in association with the HAs. Some may well have been in association with the humic matrix, and some may have been covalently linked to the humic core through, for example, the formation of Schiff... 

Poly(amino acids) are insoluble in common solvents, are difficult to fabricate due to high melting point, and absorb a significant amount of water when their acid content reaches over 50 mol%. To solve these problems, polyesters derived from amino acids and lactic acids [e.g., poly (lactic acid-co-lysine) PLAL] are developed. The PLAL system is further modified by reaction with lysine A-carboxyanhydride derivatives. Another modification of poly(amino acids) includes poly(iminocarbon-ates), which are derived from the polymerization of desaminotyrosyl tyrosine alkyl esters. These polymers are easily processable and can be used as support materials for cell growth due to a high tissue compatibility. Mechanical properties of tyrosine-derived poly(carbonates) are in between those of poly(orthoesters) and poly(lactic acid) or poly(gly-colic acid). The rate of degradation of poly(iminocarbonates) is similar to that of poly (lactic acid). 

Poly(amino acid)s (PAAs) have also been used in drug delivery PEO-(l-aspartic acid) block copolymer nano-associates , formed by dialysis from a dimethyl acetamide solution against water, could be loaded with vasopressin. PLA-(L-lysine) block copolymer microcapsules loaded with fluorescently labelled (FITC) dextran showed release profiles dependent on amino acid content. In a nice study, poly(glutamate(OMe)-sarcosine) block copolymer particles were surface-grafted with poly(A-isopropyl acrylamide) (PNIPAAm) to produce a thermally responsive delivery system FITC-dextran release was faster below the lower critical solution temperature (LCST) than above it. PAAs are prepared by ring-opening polymerisation of A-carboxyanhydride amino acid derivatives, as shown in Scheme 1. 

Several other polyamides are derived from natural poly(amino acids) that are subject to a subsequent synthetic treatment. Examples are casein, groundnut protein fiber, and zein, which after a treatment with formaldehyde led to new materials with better mechanical/solubility properties. For example, casein is a mixture of several proteins that forms 3% of milk (as casein calcium salt). Casein can be fractionated into simpler proteins designated as a, 3, y, and k [37]. The amino acid content of casein is similar to... 

Various UPE resins based on recycled poly ethylene terephthalate(PET) were prepared and the properties of the polymer mortar made with the UPE as well as those of the cured resin itself were investigated. It was found that degree of unsaturation of the resins was the most important property affecting thermal and mechanical properties of the cured resin and PM. The cured unsaturated polyester resin or polymer mortar made from resins of higher unsaturation, i.e., less PET content or adipic acid content in the resin, showed higher glass transition temperatures,... 

Part of the difficulty in interpretation may arise from the fact that in-termolecular interactions between Py-PEG-Py will also contribute to the observed Id/Im- This point was explicitly examined in the initial work on the macromolecular complexation (32, 41). In this work, it was assumed that the intermolecular contribution was simply that resulting when the intramolecular portion was subtracted from the Iq/Im value of the fully labeled PEG sample, but as Figure 2 shows, normalization to the initial solution value of I q/I before addition of the poly(carboxylic acid) did not provide much simplification. With reference to the data for the Py-PEG-Py(9200) mixed with the 40% neutralized PMAA(9500) for which no complexation occurs, we see that there are dramatic overshoots at low poly(carboxylic acid) content and plateau values at high acid content that lie either above or below the neutralized data. 

Figure 9.4 and Table 9.1 respectively show the chemical structure and the properties of these materials. Most commonly used is poly(butylene adipate-co-terephtalate) (PBAT). BASF, DuPont and Zhejiang Hangzhou Xinfu (China) manufacture and market these aromatic polyesters, under the respective brands Ecoflex , Biomax and Biocosafe . Biomax has a high terephthalic acid content, which modifies some of its properties such as the melting temperature (200°C). According to Muller et al., an increase in terephthalic acid content tends to decrease the rate of biodegradation into compost [MUL 97]. 

Jarute G, Kainz A, SchroU G, Baena JR, Lendl B (2004) On-line determination of the intracellular poly(P-hydroxybutyric acid) content in transformed Escherichia coli and glucose during PHB production using stopped-flow attenuated total reflection FT-IR spectrometry. Anal Chem 76 6353-6358... 

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