Poly system compatibility studies

The compatibility, mechanical properties, and segmental orientation characteristics of poly-e-caprolactone (PCL) blended with poly (vinyl chloride) (PVC) and nitrocellulose (NC) are described in this study. In PVC blends, the amorphous components were compatible from 0-100% PCL concentration, while in the NC system compatibility teas achieved in the range 50-100% PCL. Above 50% PCL concentration, PCL crystallinity was present in both blend systems. Differential IR dichroism was used to follow the dynamic strain-induced orientation of the constituent chains in the blends. It was found for amorphous compatible blends that the PCL oriented in essentially the same manner as NC and the isotactic segments of PVC. Syndio-tactic PVC segments showed higher orientation functions, implying a microcrystalline PVC phase. 

Dipolar spin decoupling has been used to study the numbers of contacts of various types and the free energy of formation of a single mixed contact. Sp6vacek et al. used temperature dependence of chemical shifts in H-n.m.r. spectra to examine the specific interactions in poly(methyl methacrylate) solutions. Cabane has used n.m.r. methods to study aggregation in aqueous polymer detergent systems. Compatibility and phase structure in polymer mix-... 

Detailed studies led Gandini and Plesch to formulate the concept of pseudocationic polymerisations. These are reactions which show many of the characteristics of cationic polymerisations, but do not involve ions. Since they could see no other alternative compatible with general chemical knowledge, they formulated the reactive species as an ester, and they were able to support this view by direct experiments (formation of the ester in the styrene solution by metathesis). The evidence indicates that in the system styrene, perchloric acid, methylene dichloride, the poly(styryl perchlorate) ester requires four molecules of styrene for its stabilisation. When these are no longer available, the ester ionises, and the residual styrene is consumed by a very fast, truly cationic polymerisation ionisation of the ester is a complicated reaction which has been only partly elucidated. The initiation and propagation of the pseudocationic polymerisation can be represented thus ... 

When two polymeric systems are mixed together in a solvent and are spin-coated onto a substrate, phase separation sometimes occurs, as described for the application of poly (2-methyl-1-pentene sulfone) as a dissolution inhibitor for a Novolak resin (4). There are two ways to improve the compatibility of polymer mixtures in addition to using a proper solvent modification of one or both components. The miscibility of poly(olefin sulfones) with Novolak resins is reported to be marginal. To improve miscibility, Fahrenholtz and Kwei prepared several alkyl-substituted phenol-formaldehyde Novolak resins (including 2-n-propylphenol, 2-r-butylphenol, 2-sec-butylphenol, and 2-phenylphenol). They discussed the compatibility in terms of increased specific interactions such as formation of hydrogen bonds between unlike polymers and decreased specific interactions by a bulky substituent, and also in terms of "polarity matches" (18). In these studies, 2-ethoxyethyl acetate was used as a solvent (4,18). Formation of charge transfer complexes between the Novolak resins and the poly (olefin sulfones) is also reported (6). 

More recently, Harada et al. applied the complexation process to side-chain systems via Method 6 (Figure 10), in which the guest sites were introduced as pendant groups and thereafter the CD was threaded onto them [104, 105]. Different types of hydrocarbon chain as pendant groups were studied for their compatibility with different CDs. As the cyclic was not blocked, the products can be viewed as side-chain poly(pseudo rotaxane)s of Type 9. Probably because of the rapid exchange process between threaded and unthreaded forms, the isolation of the solid-state polyrotaxane was not reported. 

Compatibility of two- and threecomponent systems of poly(vinyl chloride) with homo- and copolymers of methyl methacrylate and butyl methacrylate has been studied. The mixtures were tested for compatibility in the dynamic viscosity of polymer solutions, in microscopic observations in polarized light, as well as by dynamic mechanical measurements. It was found that poly(methyl methacrylate) and methacrylic copolymers were compatible with PVC. Poly(butyl methacrylate) appears to be incompatible with PVC. Estimation of solubility parameter values 6 made it possible to predict the compatibility of polymer pairs. Critical A6 value for compatible polymers has been found to be 0.5 (cal cm 3)1/2. 

Studying other systems, Noland et al (1971) presented data based on differential thermal analysis (DTA), thermomechanical analysis, and dilatometry to show that mechanical blends of poly(methyl methacrylate) and poly(ethyl acrylate) are compatible with poly(vinylidene fluoride)... 

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