CAPROLACTAM COPOLYMER

Table 12.7 Thermal Stability of Phthalamide-Caprolactam Copolymers...

Coefficient of Friction and Wear Rate of Styrene- -Caprolactam Copolymers of Varying... 

Rranco, T. T., Galaev, I. Y, Hatti-Kaul, R., Holmberg, N., Bu, L., Mattiasson, B. (1997). Aqueous two-phase system formed by thermoreactive vinyl imidazole/vinyl caprolactam copolymer and dextran for partitioning of a protein with a poly histidine tail. Biotechnology Techniques, II, 231-236. 

Vinyl acetate/vinyl caprolactam copolymer water 93PAS... 

Vinyl amine/vinyl caprolactam copolymer water water 91 TAG 94TAG... 

Reaction Injection Molding. RIM uses the anionic polymeri2ation of nylon-6 to carry out polymeri2ation in the mold. A commercial process involves the production of block copolymers of nylon-6 and a polyether by mixing molten caprolactam, catalyst, and polyether prepolymer, and reacting in a mold (27,28). 

Block, Gr ft, ndSta.r Copolymers. A host of copolymers of these types have been prepared. They iaclude block copolymers from S-caprolactam and PTMEG as well as block copolymers from PTHF and other cationicaHy polymerizable heterocycles, including... 

Another important type of condensation polymer are the linear polyesters, such as poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT). Copolymers of polyesters and PA have been studied in detail, and it has been shown that random copolyesteramides have a low structural order and a low melting temperature. This is even the case for structurally similar systems such as when the group between the ester unit is the same as that between the amide unit, as in caprolactam-caprolactone copolymers (Fig. 3.10).22 Esters and amide units have different cell structures and the structures are not therefore isomorphous. If block copolymers are formed of ester and amide segments, then two melting temperatures are present. 

Figure 3.10 Melting temperatures of caprolactam-caprolactone random copolymers as function of molar composition.22...

Anionic copolymerization of lactams presents an interesting example of copolymerization. Studies of the copolymerization of a-pyrrolidone and e-caprolactam showed that a-pyrrolidone was several times more reactive than e-caprolactam at 70 °C, but became less reactive at higher temperatures due to depropagation210 2U. By analyzing the elementary reactions Vofsi et al.I27 concluded that transacylation at the chain end occurred faster than propagation and that the copolymer composition was essentially determined by the transacylation equilibrium and the acid-base equilibrium of the monomer anion together with the usual four elementary reactions of the copolymerization. 

Anionic copolymerization of e-caprolactam and cj-caprylolactam was also reported212,213. Organosiloxane copolymers can be prepared from two different cyclics by using acid or base catalysts214. ... 

Anionic polymerization of lactams was shown to proceed according to what is called the activated monomer mechanism. With bischloroformates of hydroxy-terminated poly(tetramethyleneglycol) and poly(styrene glycol) as precursors for a polymeric initiator containing N-acyl lactam ends, block copolymers with n-pyrrol-idone and e-caprolactam were obtained by bulk polymerizations in vacuum at 30 and 80 °C, respectively361. ... 

Synthesis of PDMS-b-(e-caprolactam) ABA block copolymers was reported 343 In these reactions, anhydride-terminated PDMS oligomers were used to initiate the polymerization of -caprolactam in the presence of a catalytic amount of sodium hydride in melt at 130 °C. Under these conditions, the reaction was reported to be completed in... 

On-line SFE-pSFC-FTIR was used to identify extractable components (additives and monomers) from a variety of nylons [392]. SFE-SFC-FID with 100% C02 and methanol-modified scC02 were used to quantitate the amount of residual caprolactam in a PA6/PA6.6 copolymer. Similarly, the more permeable PS showed various additives (Irganox 1076, phosphite AO, stearic acid - ex Zn-stearate - and mineral oil as a melt flow controller) and low-MW linear and cyclic oligomers in relatively mild SCF extraction conditions [392]. Also, antioxidants in PE have been analysed by means of coupling of SFE-SFC with IR detection [121]. Yang [393] has described SFE-SFC-FTIR for the analysis of polar compounds deposited on polymeric matrices, whereas Ikushima et al. [394] monitored the extraction of higher fatty acid esters. Despite the expectations, SFE-SFC-FTIR hyphenation in on-line additive analysis of polymers has not found widespread industrial use. While applications of SFC-FTIR and SFC-MS to the analysis of additives in polymeric matrices are not abundant, these techniques find wide application in the analysis of food and natural product components [395]. 

Evidently, there are a number of factors that determine which of the above-mentioned pathways of polymerization occurs. One of these is the enrichment of final copolymers with the more hydrophilic comonomer (in comparison with the composition of the initial feeds), due to a higher reactivity of NVIAz. The higher (than for NVC1) reactivity of NVIAz is determined by a stronger polarization of the double bond of the vinyl group by the imidazole moiety as compared with the caprolactam cycle. Furthermore, a good solubility of hydrophilic NVIAz can also contribute to its higher reactivity in aqueous media. 

Liquid PA or cast nylon is a block copolymer of caprolactam and a prepolymer that can be processed in the liquid state, which simplifies tooling and processing machines. 

There are numerous bifunctional monomers used in condensation polymerization. Some of the more popular signature groups that turn up frequently are shown in Figure 22-3. Important copolymers made by condensation include epoxies, nylon, polyesters, polycarbonate, and polyimides. As always, there are exceptions, and one is Nylon 6 made by a ring opening reaction of caprolactam. All of these will be covered in the next two chapters. 

Nylon-6, structurally quite similar to nylon-6,6, was initially produced in Germany by the ROP of caprolactam, partly as a way to avoid the patents established by DuPont a decade earlier. The copolymer of nylon-6 and nylon-6,6 has a smoother surface than either of the homopolymers ... 

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