Heterophasic propylene-ethylene copolymers HPEC

To illustrate the potential of the method, we present in Figure 7 the 2D ESRI perspective plot of a phantom sample consisting of nitroxide biradicals derived from Tinuvin 770 (obtained by oxidation of the amine) in two different environments in a plaque of heterophasic propylene-ethylene copolymers (HPEC). One side of the plaque was doped with the biradical by contact with a biradical solution in toluene. The same biradical solution was placed on transparent tape and the solvent was evaporated the tape was then folded and attached to the other side of the plaque. The corresponding spectral slices are... 

Fig. 4. The ID ESRI at 340 K of a cylindrical sample (height 3 mm, diameter == 4 mm) of heterophasic propylene-ethylene copolymer (HPEC) containing a nitroxide derived from a hindered amine stabilizer (HAS). X-band ESR spectrum recorded in the absence (a) and in the presence of a vertical magnetic field gradient of 206 G cm b).

Our laboratory developed ID and 2D spectra-spatial ESRI for the study of het-erophasic systems, such as poly(acrylonitrile-butadiene-styrene) (ABS) and heterophasic propylene-ethylene copolymers (HPEC) containing bis(2,2,6,6-tetram-ethyl-4-piperidinyl) sebacate (Tmuvin 770) as the HAS, and exposed to thermal treatment and UV irradiation.The major objectives were to examine polymer degradation under different conditions to assess the effect of rubber phase (polybutadiene in ABS and ethylene-propylene rubber in HPEC) on the extent of degradation and to evaluate the extent of stabilization by HAS. The repeat units in ABS and the formula of Tinuvin 770 are shown in Fig. 2. 

Heterophasic propylene-ethylene copolymers (HPEC) consist of crystalline polypropylene (PP) modified by an elastomeric component, typically ethylene-propylene rubber (EPR), and are prepared by polymerization of propylene (P) in the presence of catalysts, and sequential polymerization of a propylene-ethylene mixture with... 

This section presents the ID and 2D ESRI study of thermally and UV-treated heterophasic propylene-ethylene copolymers (HPEC) polymers. Two polymers, coded HPECl and HPEC2, differing in ethylene content, were investigated. The ethylene content was 25% wt in HPECl and 10% wt in HPEC2, within 2%, as determined by FTIR. Morphologically, HPEC systems are more complex compared to ABS, because of the presence of amorphous and crystalline domains. 

Figure 14 presents the 2D spearal-spatial ESRI perspective plot and corresponding virtual slices for nitroxide radicals derived from hindered amine stabilizers (HASs) generated during the UVB irradiation of heterophasic propylene-ethylene copolymers (HPEC). " Note that the ESR spectra shown in the spectral slices consist of two spectral components, F and S, whose relative intensities vary as a function of sample depth, from about 22% near the irradiated side to about 45% at the other sample extremity. Data such as those shown in Figure 14... 

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