Polyethylene measurements

Figure 19.7. Fatigue resistance of acetal resin compared with nylon 66 and with polyethylene. Measured as the cycles to failure at a given applied stress. (Du Pont trade literature)...

In Fig. 15.27, the transient extensional viscosity of a low-density polyethylene, measured at 150 °C for various extensional rates of strain, is plotted against time (Munstedt and Laun, 1979). Qualitatively this figure resembles the results of the Lodge model for a Maxwell model in Fig. 15.26. For small extensional rates of strain (qe < 0.001 s ) 77+(f) is almost three times rj+ t). For qe > 0. 01 s 1 r/+ (f) increases fast, but not to infinite values, as is the case in the Lodge model. The drawn line was estimated by substitution of a spectrum of relaxation times of the polymer (calculated from the dynamic shear moduli, G and G") in Lodge s constitutive equation. The resulting viscosities are shown in Fig. 15.28 after a constant value at small extensional rates of strain the viscosity increases to a maximum value, followed by a decrease to values below the zero extension viscosity. 

Figure 3. Polyethylene measured energy loss function, Im(—l/e) ( ). Results of a Kramers-Kronig analysis e,(--------------) (---) (i).

Other. As a result, the difference between the crystalline and amorphous phases appears in the relaxation times and chemical shifts. Fyfe et al. [1] and Earl and VanderHart [2] independently observed the chemical shift difference between the crystalline and amorphous phases for polyethylene. Figure 7.1 shows a spectrum of polyethylene measured by the CPMAS method. If all of the methylene units in polyethylene are identical, the NMR spectrum gives only one peak. However, a strong peak and shoulder are observed in the real spectrum, which means that there exists two inequivalent methylene units in the solid polyethylene. From measurements on polyethylenes with various crystalline/amorphous ratios, peaks at about 33 and 31 ppm are attributed to the crystalline and amorphous phases, respectively [3]. Figure... 

Fig. 7.2. Recovery of peaks for the crystalline and amorphous phases of polyethylene measured by (180° - T - 90° - 100 s) with high-power decoupling.

Fig. 7.13. C MAS spectra of polyethylene measured by four pulses (CP, SL20 + CP,...

Fig. 7.21. (a) CPMAS NMR spectra of melt-quenched polyethylene measured as a function of temperature, and (b) expanded CPMAS NMR spectra at temperatures from -50 to -120°C [20]. 

Fig. 3 Influence of molar mass on properties of polyethylene (measured at 23°C)...

Fig. 4.4 Effect of various additives on smoke production of polyethylene measured...

Temperature dependence of the shear modulus G and logarithmic deaement A of linear (LPE) and branched (BPE) polyethylene. Measurements by torsion peixjulum at frequency 1 Hz. The relaxation processes are labelled a for that at the highest temperature, j3 for that at the next highest temperature, and so on. The obsen/ation of the o-process in aeep for LPE is shown in Figure 4.4 (after Flocke). 

The DTA heating curves of polyethylene measured over a range of pressures are presented in Figure 2.4. 

The underwater coincidence counter (UWCC) is a transportable system for measuring fresh MOX fuel stored under water (Eccleston et al. 1998). It is a modified version of a standard Fork detector (FDET) whereby the ionization and fission chambers have been replaced with sensitive He tubes embedded in a high-density polyethylene measurement head. The UWCC measures neutrons coming from a segment of the MOX fuel in multiplication corrected coincidence mode and provides total Pu, once the isotopics and the active fuel length are known. 

Fig. 13a. FTIR spectra taken at 300 K during elongation of a high-density polyethyloie film with light polarized alternately parallel and perpendicular to the stretching direction b Stress-strain diagrams of high-density polyethylene measured at 300 K and 343 K...

Commercial high-pressure DTA instruments use an inert purge gas to attain a maximum operating pressure of 10 MPa. The DTA heating curves of polyethylene measured over a range of pressures are presented in Figure 2.16. 

Figure 5 a) Optical absorption coefficient of poly(di-n-hexylsilane), calculated from the reflectivity measurements shown in figure 2. b) Absorbance of polyethylene, measured by Ifiishimoto et. al [24]. 

Typical number average molecular masses of some different polyethylenes measured by three different thermal analysis techniques ... 

Table 33 Ketonic groups formed in UV irradiated polyethylene measured by IR absorption [2128]...

G. Fleischer, "Self-diffusion in Melts of Polystyrene and Polyethylene Measured by Pulsed Field Gradient NMR," Polvm. Bull. 2., 152-158 (1983). 

FIGURE 4.54 A peak in the DATR spectrum of polyethylene measured with angles of incidence from 42° to 70°. The peaks are of different sizes because the depth of penetration changed with angle of incidence. 

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