Polyamide oligomer

Hyphenation in capillary electrophoresis is still in its infancy. Critical aspects of CE hyphenation include the minute volumes of sample injected (typically a few nL) and small flow-rates (in the order of nLmin-1). Interfaces are not commercially available. CZE-UV can be used for the analysis of higher polyamide oligomers in HF1P solution [859]. A solvent elimination design with nebuliser has been described for CE-FTIR and CEC-FTIR coupling absolute detection limits are hundreds of pg [860]. An advantage of CE-FTIR is that analytes may be detected and identified without derivatisation. CE(C)-NMR [861-863] is advancing rapidly. 

Copolymers of methacrylic add and ethylene termed as ethylene ionomers have been used as the base polymer for binding alkali, alkaline earth and transition metal ions. Organic amines such as n-hexylamine, hexamethylene tetraamine, 2,2,6,6-tetramethyM-hydroxy piperazine, ethylene diamine and polymeric diamines such as silicone diamine, polyether diamine and polymeric diamines such as silicone diamine, polyether diamine and polyamide oligomers considerably enhance the complex formation characteristics of Zn(II) ethylene ionomers thereby enhancing the physico-chemical properties [13]. 

Synthesis of piperazine-terminated oligomers as prepolymers for interfacial membrane formation was also examined.46 48 Excess piperazine was reacted with di- and triacyl chlorides in an inert solvent such as 1,2-dichloroethane. The resulting amine-terminated polyamide oligomers had low solubility in the solvent system and precipitated. This served to limit the degree of polymerization of the oligomer. Even so, a portion of the product was insoluble in water and was filtered out during preparation of the aqueous oligomeric amine solution for the interfacial reaction step. 

SOLUBLE Aliphatic secondary amides, stearic acid, aliphatic esters, polyamide oligomers... 

Later the same polymerization technique proved to be successful in the preparation of multiblock copolymers from poly(oxyethylene)dicarboxylic acid and a polyamide oligomer based on bis(4-aminophenyl)ether and isophthalic acid. The synthesis could be carried out either by a one-pot two-step method [52] or using a two-pot technique by first isolating the polyamide oligomer [11]. The two approaches lead to copolymers with similar thermal and mechanical properties, though this was not the case when a one-pot, one-step method was used [52], probably because of the formation of a more irregular structure. 

Pradet and co-workers [60] have presented an original preparation of polyether-6-amide copolymers using a chain-coupling reaction between 4,4 -disub-stituted bisoxazolones and a mixture of amine-terminated polyethers and polyamide oligomers (Figure 4). The reaction could be carried out in a one- or... 

PCL-polyamide multiblock copolymers were synthesized by linear chain extension of PCL diol and diamine-terminated polyamide oligomer with HDI in DMF (Scheme 7). The sample designation in Table 8 indicates the molecular weight and the content of PCL block, as well as the type of the polyamide block... 

PCL diol oligomer PCL diol Polyamide oligomer HDI PCL diol Polyamide oligomer HDI dL/g... 

Fatty acids, both saturated and unsaturated, have found a variety of applications. Brassilic acid (1,11-un-decanedicarboxylic acid [BA]), an important monomer used in many polymer applications, is prepared from erucic acid (Scheme 2), obtained from rapeseed and crambe abyssinica oils by ozonolysis and oxidative cleavage [127]. For example, an oligomer of BA with 1,3-butane diol-lauric acid system is an effective plasticizer for polyvinylchloride. Polyester-based polyurethane elastomers are prepared from BA by condensing with ethylene glycol-propylene glycol. Polyamides based on BA are known to impart moisture resistance. 

TDI isomers, 210 Tear strength tests, 242-243 TEDA. See Triethylene diamine (TEDA) Telechelic oligomers, 456, 457 copolymerization of, 453-454 Telechelics, from polybutadiene, 456-459 TEM technique, 163-164 Temperature, polyamide shear modulus and, 138. See also /3-transition temperature (7)>) Brill temperature Deblocking temperatures //-transition temperature (Ty) Glass transition temperature (7) ) Heat deflection temperature (HDT) Heat distortion temperature (HDT) High-temperature entries Low-temperature entries Melting temperature (Fm) Modulu s - temperature relationship Thermal entries Tensile strength, 3, 242 TEOS. See Tetraethoxysilane (TEOS)... 

The development of the aminoethylglycine polyamide (peptide) backbone oligomer with pendant nucleobases linked to the glycine nitrogen via an acetyl bridge now often referred to by PNA (peptide nucleic acid Fig. 4.1), was inspired... 

This field has also inspired the development of a range of pseudo-peptides, that is polyamides composed of amino acids other than a-amino acids. These include for instance peptoids, /9-amino acid oligomers and also compounds such as peptide nucleic acids and DNA binding polyamides, all of which share the amide (peptide) chemistry with natural peptides. 

While additive analysis of polyamides is usually carried out by dissolution in HFIP and hydrolysis in 6N HC1, polyphthalamides (PPAs) are quite insoluble in many solvents and very resistant to hydrolysis. The highly thermally stable PPAs can be adequately hydrolysed by means of high pressure microwave acid digestion (at 140-180 °C) in 10 mL Teflon vessels. This procedure allows simultaneous analysis of polymer composition and additives [643]. Also the polymer, oligomer and additive composition of polycarbonates can be examined after hydrolysis. However, it is necessary to optimise the reaction conditions in order to avoid degradation of bisphenol A. In the procedures for the analysis of dialkyltin stabilisers in PVC, described by Udris [644], in some instances the methods can be put on a quantitative basis, e.g. the GC determination of alcohols produced by hydrolysis of ester groups. 

Many analytical techniques are in use for the qualitative and quantitative evaluation of monomers and oligomers extracted from PA6 (GC, differential refrac-tometry, IR, PC, SEC, HPLC, RPLC, etc.). FTIR has been used for quantitative analysis of caprolactam oligomer content (extract %) in polyamide-6 [113], The method, which involves a 3h extraction in boiling methanol, is suitable for process control and plant environment. Kolnaar [114] has used FTIR characterisation of fractional extracts with pentane, hexane, and heptane of HDPE for blow moulding applications. Vinyl acetate in packaging film has similarly been determined by quantitative FUR. 

FIGURE 17.19 2D contour plot of a modified polyamide 6, first dimension LCCC, second dimension SEC. Area 1 unmodified chains, area 2 modified chains, area 3 cyclic oligomers. (See color plate.)... 

There are two different oligomer series present in all spectra. The oligomer series can be identified by calculating the masses of the end groups and assigning them to specific chemical structures (Pasch and Schrepp, 2003 Weidner et al., 2004). In the present example, the two species are the propionic amide-acid (R-am-ac) and the propionic amide-propionic amide polyamides (R-am-am-R). The use of MALDI-TOF MS as a structure-sensitive detector allows the resolution to be indirectly enhanced since several species coelute, as shown in Fig. 17.21. The polarity of the... 

The molecular weights of the polymers before and after irradiation were followed by GPC to determine changes in the molecular weights of the polyamides. It was found that photolysis of the polymer resulted in polymer chain scission, leading to the appearance of oligomers containing thymine bases at the end of the molecules. 

Estimation of Molecular Weight Distribution of Polyamide Blocks. The molecular weight distribution of the polyamide blocks was estimated by gel permeation chromatography (GPC) using two instruments, model HLC-802R (Toyo Soda Industry Co., Ltd.) and model GPC-2i U (Waters Associates, Inc.). Polystyrene and nylon oligomer were used as standards. 

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