Poly against time

FIGURE 15.16 Comparison of loading tests using 1000-kg load on crates made from (a) high-density polyethylene and (b) poly(ethylene Z -propylene) copolymer. The percentage compressive strain 8, is plotted against time t. (After Willboum, A.H., Plastics and Polymers, 417, 1969. With permission.)... 

Figure 3.5 Experimental (triangles for lnP , squares for InP ) and calculated (continuous lines) number average and weight average molecular weight for poly(lactic acid) films against time. From Nishida, H., Yamashita, M., Nagashima, M., Hattori, N., Endo, T., Tokiwa, Y., 2000. Theoretical prediction of molecular weight on autocatalytic random hydrolysis of aliphatic polyesters. Macromolecules 33, 6595—6601.

FIG. 18-11. Tensile creep compliance plotted against time with a logarithmic scale for poly(vinyl chloride) quenched from 90°C to 40° and aged for varying periods as shown up to 1000 days. Curve at right contains all points after shifts as in Fig. 18-10 (almost no vertical shift). (Struik. ) Reproduced, by permission, from Physical Aging in Amorphous Polymers and Other Materials, by L. C. a Struik, Elsevicr/North Holland Biomedical Press, 1978. 

Fig. 1. Nonnalized dectrica%4idiiced optical bireftingeiice against time folkywiiv a rectangular pulse for a poly(phenylmethylsiloxane) at 211.7 K...

Fig. 9.8 Plot of spherulite growth rates against time for poly(ethylene adipate), M = 9900, at indicated crystallization temperatures. (From Takayanagi (23))...

Fig. 10.19 Plot of melting temperature against time after isothermal crystallization, at indicated temperatures, of a hydrogenated poly(butadiene), 2.3 mol percent branch points, = 108 000.(24)...

Fig. 13.14 Log-log plot of ln(l - X) against time for isotactic poly(propylene), Mw — 3.6 X 10, crystallizing from a 0.3% decalin solution. X represents the fraction transformed. (From Shah and Lahti (35))...

As an example of the form of the information that may be derived from a pyrolysis-MS, Figure 26 [69] shows the structure of the polycarbonate (PC) and the EI-MS spectra of pyrolysis compounds obtained by DPMS of poly(bisphenol-A-carbonate) at three different probe temperatures corresponding to the three TIC (total ion current) maxima shown in Figure 27(b) Figure 27 compares the MS-TIC curve with those obtained from thermogravimetry. (The TIC trace is the sum of the relative abundances of all the ions in each mass spectrum plotted against the time (or number of scans) in a data collection sequence [70].)... 

Degradation of 5 -terminal sequences in luciferase mRNA containing 60-nt poly(A) tract and capped with the indicated anti reverse cap analogs. The mRNAs half-lives were determined by real time PCR with primers directed against the 5 -end of luciferase mRNA as described in the text. 

Dual lifetime referencing (DLR) is another powerful technique that enables referenced measurements in case of fluorescent indicators [23]. In this method, the analyte-dependent signal from an indicator is referenced against the signal from an inert luminophore. This can be realized in both the time domain [24] and in the frequency domain [25]. Often, a luminescent reference dye is embedded into gas blocking nanobeads to avoid oxygen quenching. Polymers with very low gas permeability such as poly(acrylonitrile) [24] or poly(vinylidene chloride-co-acry-lonitrile) [26] are the best choice here. 

Results for the challenge of coated glass with S. aureus are shown in Table 1. The time of chlorination was a function of the hydrophilicity of the surface coating the poly(vinyl acetate oxazolidinone) polymers required the least amount of exposure to free chlorine. All of the surface coatings were effective against S. aureus in brief contact times. The grafted poly(acrylonitrile oxazolidinone) sample was not tested until 30 days after chlorination, but it still provided a 6-log inactivation of S. aureus in less than 10 min of contact. 

Poly(aorylonitrile-co-oxazolidinone), 2 = poly(vinyl aoetate-co-oxazolidinone), 3 = poly(acrylonitrile-g-oxazolidinone), 4 = poly(vinyl aoetate-g-oxazolidinone), 5 = poly(vinyl alcohol-g-oxazolidinone). Coatings were soaked in 3,000 mg/L free ohiorine. Time after ohiorination when biooidal effioaoy was measured. TABLE 2. Zones of inhibition of A/-Chioramine Poiymerio Biooidai Coatings on Fabric against Staphylococcus aureus. ... 

Of the remaining materials in Table IV, only Viton, neoprene rubber latex,poly(vinyl alcohol), butyl rubber, and butyl-coated nylon exhibited at least a 20-min breakthrough time forl,2 dichloro-ethane permeation to occur. The nitrile rubber latex, cement dipped nitrile rubber, polyethylene (medium density), and surgical rubber latex were all penetrated by 1,2-dichloroethane in less than 3 min and would be of little use in situations requiring the garment to be in constant contact with 1,2-dichloroethane. From the above, butyl rubber or Viton appear to be the best materials to protect the worker against 1,2-dichloroethane, but because of apparent lot-to-lot variations(20) in butyl properties, Viton appears to be the best suited material of these studies to protect the worker from this chemical. 

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