Irradiation reaction blending

Also, it is apparent that the gel content of irradiated blends can be higher than that expected if the gelation was entirely due to the reaction of homopolymer PDMS. We can eliminate the possibility that PS is responsible for this deviation since previous results indicate that gel formation in the PS used does not take place below 200 Mrad. There are two possible explanations the first is that some PS is "trapped" (not bound) within the PDMS gel, and cannot be extracted from the matrix. The other is that the PDMS is undergoing a higher degree of cross-linking, as a result of a reduction in chain scission. 

Neutral alumina (20 g) was stirred for 15 min with an aqueous solution of KF (15 g KF/150 mL H20). The mixture was concentrated to dryness under vacuum and kept at 100 °C for 30 min. The reagent (15 mmol) was intimately blended with KF/AI2O3 (4xreagent mass), epoxyisophorone (1.54 g, 10 mmol) was quickly added to the support and immediately heated in an oil bath or exposed to microwave irradiation. When the reagent was solid, it was dissolved into 5 mL CH2CI2 and mixed with the solid support, and the solvent was evaporated to dryness. At the end of the reaction, the products were eluted from the solid support by washing with 3x10 mL methylene chloride. 

The formation of keto-phosphonate structure within macromolecule leads to the removal of internal unsaturation. Triallyl cyanurate and ionizing irradiations [210] made a E-P block copolymer-PE blend thermally stable. Triallyl cyanurate increases the crosslinking density probably due to addition reactions between polymeric and allyl radicals produced by ionizing radiation. The addition of 2,2,4-trimethyl-l,2-di-hydroquinoline and bis[4(l-methyl-1-phenylethyl)pheny 1]-amine stabilized a PE-EPDM blend against heat [211]. Popov et al. [212] studied the ozone effect on PE-iPP blend. The oxidation rate was detected in relation to... 

Ozone and Organic Oxidants. When a blend of 10 pphm NO2 in air was irradiated under the same experimental conditions used to obtain the data of Figure 1, O3 and NO increased to about 1.2 pphm within the first five minutes of irradiation. Their concentrations remained at that value during the 120-minute experiment. This buildup and attainment of steady state is attributed to the rapid synthesis of NO and ozone, according to Reactions 1 and 2, and at equilibrium to the equally rapid removal of NO and O3 by Equation 3 ... 

A blend containing 10% of PMMA was similarly irradiated at 150 C. The only significant volatile product was methyl methacrylate and the weight loss, corresponding to the amount of the PMMA blended, was complete after 5 hours. Infra-red spectral measurements indicated the complete absence of methacrylate in the residue. At all irradiation times up to 5 hours the methacrylate content of the blend is completely separable from the PP by acetone extraction. Thus, these experiments could provide no positive evidence of reaction of either PMMA radicals or methyl methacrylate monomer with PP radicals, all of which were known to be present in the system. 

The importance of the reduction of the stability of the PP component by pre-irradiation in determining the course of the degradation reaction is further emphasized by the TVA thermogram in figure 13, which demonstrates that the "Interaction" peak due to monomer is at least as prominent as in un-lrradlated blends (figure 8B). 

Grafting of functional side-groups without forming long polymer chains may be achieved in a similar way by the reaction of activated polymeric materials with low molecular weight compounds carrying functional groups of appropriate reactivity. The physical stabilization of unstable blends of amorphized starch with reactive plasticizers has been achieved by EB-irradiation [11 ]. 

In comparison experiments, we used two samples, each with 1.2 wt ABP - oneanE/ABP copolymer and the other an E//E/ABP blend. Due to the sample thickness (2 mils) and the high ABP concentration, nearly 100 of the incident radiation was absorbed by the samples in the initial part of the reaction. The samples were irradiated for various periods and the gel fractions and crosslink densities determined. These data are tabulated in Table IV and plotted in Figure 5. 

Rizzo et al. [1983] investigated changes in the physico-chemical properties caused by gamma irradiation of LDPE/PP blends (100 0, 75 25, 50 50, 25 75, and 0 100) (Table 11.9). On irradiation of the individual polymers with 1500 kGy dose, the gel fraction was obtained as 95% in LDPE and 65% in PP. On irradiation of the blends the gel fraction increased with the LDPE-content and dose. On irradiation under vacuum, the crosslinking reactions predominated in LDPE, as discussed in Section 11.3.1. In the case of PP, accumulation of unsaturation with increasing dose contributes to extensive crosslinking at the high dose used here (1500 kGy), as discussed in Section 11.3.2. 

In the irradiated LLDPE, they observed the formation of both hydroxyl groups and carbonyl groups, as a result of radiation-induced oxidative degradation (through reactions such as (R-22), and (R-26 to R-29)). Both the elongation at break, and the Izod impact strength of the blends... 

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