Absorption characteristics polymers

The polymers combine a high level of flame retardancy with good thermal insulation and sound absorption characteristics. Densities are somewhat high (16-20 kg/m ). 

VC=C n the yellow solution. In both cases the experimental data are quite well represented considering that there is only one parameter in the fit. The model also adequately describes the Raman excitation profile. The good agreement between the model and the experimental results confirms the basic premise of the model that the individual polymer chains in solution contain a distribution of chain lengths which determine the absorption characteristics of the solutions. 

Another interesting chiral chain end effect is exhibited by the helical polymer block co-polymer, poly(l,l-dimethyl-2,2-di-/z-hexylsilylene)- -poly(triphenylmethyl methacrylate), reported by Sanji and Sakurai (see Scheme 7) and prepared by the anionic polymerization of a masked disilene.333 The helical poly(triphenylmethyl methacrylate) block (PTrMA) is reported to induce a PSS of the same sign in the poly(di- -propylsilylene) block in THF below — 20 °C, and also in the solid state, by helicity transfer, as evidenced by the positive Cotton effect at 340 nm, coincident with a fairly narrow polysilane backbone UV absorption characteristic of an all-transoid-conformation. This phenomenon was termed helical programming. Above 20°C, the polysilane block loses its optical activity and the UV absorption shifts to 310 nm in a reversible, temperature-dependent effect, due to the disordering of the chain, as shown in Figure 45. 

Polymer Engineering and Science 42, No.6, June 2002, p. 1274-85 DEFORMATION AND ENERGY ABSORPTION CHARACTERISTICS OF MICROCELLULAR ETHYLENE-OCTENE COPOLYMER VULCANIZATES Nayak N C Tripathy D K Indian Institute of Technology... 

The effect of the type and level of initiator on polymerization time, monomer conversion, and polymer molecular weight, the effect of polymerization temperature on the crystallization behavior of the polyamide generated, and the role of a higher lactam like laurolactam on the moisture absorption characteristics of the copolymers are discussed in our previous publication [23]. 

The structures of a number of commercially available 2-hydroxyphenylbenzotriazoles are summarised in Table 2. Substituents in both the phenol ring and the benzotriazole ring affect the absorption characteristics and the stability of these compounds. The size of the substituents is also important in determining the volatility of these stabilizers and their compatibility with polymer systems. 

However we have not yet been able to accomplish differentiation for EDG = Me2N. Thus by controlling the size of the oligomeric segment we predetermine the delocalization length of the polaronic or bipolaronic domain as well as the absorption characteristics of the polymer in either pristine or oxidized form. 

Han and Elsenbaumer also note that the BP initially formed can react with neutral polymer to form two distinctly different polarons via interchain electron transfer. After twenty-four hours, our optical spectra are unchanged, and have measurable ESR activity. However, in contrast to alkoxy-PPV polymer, we do not observe a typical polaronic absorption spectrum, but rather one almost identical to the bipolaron obtained from SbCl5 doping of 10-5 M solutions in CH2CI2. A possible interpretation is one which allows for P and BP states coexisting in dynamic equilibrium, with the bipolaron dominating the optical absorption. The absorption characteristics of the protonically doped polyenes are shown in Table II compared to the same samples doped with SbCl5. 

Noncovalent approaches can usually preserve the structures and properties of carbon nanotubes after functionalization17 (though not necessarily the near-infrared absorption characteristics due to well-established doping effects), thus are equally important to the biocompatibilization and bioapplications of nanotubes.15 Among commonly employed noncovalent schemes are surfactant dispersion,18 tt-tt stacking with aromatic compounds,19 and polymer wrapping.20... 

Infrared Spectra of Grafted Bamboo. It has been demonstrated that the occurrence of graft copolymerization of methyl methacrylate onto bamboo can be accertained by the presence of characteristic absorptions of polymer branches in the infrared spectrum (17-19), in addition to the weight increased in bamboo samples. In this study, similar procedures were conducted for the grafting of acrylonitrile. The formation of graft copolymer could easily be detected by the... 

In solution, the UV absorption characteristics of polygermanes may be different from those in the solid state. Poly(dihexyl)germane in solution has a kmax value of 327 nm, whereas the same polymer fraction deposited as a thin film on a quartz plate exhibits two... 

Absorption Characteristics of Polypropylene. In discussions of the degradative effects of ultraviolet radiation, and photostabilization of polypropylene, absorption characteristics of the polymer as well as the energies involved should be considered. 

Besides the polymer derivatization, combining the polymers in microsphere preparations can result in improved drug delivery and absorption characteristics. Hyaluronic acid-chitosan microspheres appeared to improve the absorption of incorporated gentamicin compared to the individual polymers, assembling the mucoadhesive potential of both polymers and the penetration-enhancing effect of chitosan [51,52],... 

Table 7.17 Infrared Absorption Characteristics of Electrodeless Glow Discharge Polymers... 

---