Phase types, combined polymers

In multiphase filled polymer compositions, which may contain mixed filler types, combinations of fillers and fibres, or proportions of filler and a secondary modifying polymer, such as an elastomer, the spacial distribution of the phases has a direct bearing on the properties of the composite. In the case of the last mentioned system, the rubber may encapsulate the filler, be present as discrete droplets within the thermoplastic matrix or co-exist in both structural forms [80,81]. 

By building - in combinations of aromatic rings into the polymer chains, chemists are able to produce polymer chains with very low chain flexibility. In the limit they reach rigid-rod-type op polymers. Such polymers show substantial temperature - pressure -concentration regions in which the stiff polymer chains arrange in some form of orientation. This phase behaviour gave them the name Liquid Crystalline Polymers (LCP) and LCP have unique properties. 

Generally, to fit the observed FID, a series of exponential functions (Equation (1)) are used because the distribution of dipole interaction is expressed by Lorentzian function. This is true for the solution, melt and amorphous phases of the polymers. Actually, a PE melt with low MW exhibits a single exponential curve.14-17 The shape of the relaxation curve of amorphous molecular motion still retains the combined exponential types on cooling. On the other hand, Weibullian functions (Equation (2))6 18 are also applicable for the phase with partially restricted motion such as the interfacial phase.19 Therefore, it is reasonable to introduce the exponential and Weibullian functions as the amorphous relaxation ... 

Most of the methods developed in this book are, by themselves, only applicable to amorphous polymers and amorphous polymeric phases. (An exception with obvious relevance to the properties of multiphase materials is the development of a physically robust predictive model for the shear viscosities of dispersions in Section 13.H.) Their combination with other types of methods to predict the properties of multiphase materials from component properties and multiphase system morphology enables us to expand their applications to include the prediction of selected properties of multiphase polymeric systems where one or more of the phases are amorphous polymers. In other words, the methods developed in this book are used to predict the properties of the amorphous polymeric phases of the multiphase system. These properties are then inserted into equations of composite models and into numerical simulation schemes (along with material parameters of the other types of components, obtained from other sources such as literature tabulations) to predict the properties of the multiphase system. We use existing composite models whenever they are adequate, and develop our own otherwise. 

Pyrimidines are an interesting class of nitrogen-containing heterocycles which display a broad range of useful properties.Based on a novel cyclocondensation reaction between acetylenic ketones of type 339 and polymer-bound isothiourea 338, Obrecht et developed a versatile and efficient solid-phase synthesis of polymer-bound 2-(alkylthio)-4,6-disubstituted pyrimidines 340, and combined this protocol with the nucleophilic displacement reaction of the 2-sulfonyl group of pyrimidines 47 j gy dgavage reaction. In addition, simple... 

Any combination of the above two types of polymer can form thermoplastic IPNs in which some degree of dual-phase continuity is attained. Some of the thermoplastic IPNs have been claimed to be tough materials (44, 45). Though tribological properties of these new materials have not been investigated, they should be of... 

In polymer solutions and polymer blends, LCST, UCST, combined UCST and LCST, hourglass, and closed-loop shaped phase diagrams have been found experimentally. These five types of phase diagrams are the most commonly observed phase diagrams in polymer systems. An important role is played by temperature in the phase diagrams according to the equation ... 

Thermoplastic elastomers (TPEs) combine the physical properties of vulcanized rubber with the ease and economy of conventional thermoplastic processing. They are also well suited to reprocessing and recycling and minimize toxicity issues. Many types of thermoplastic elastomers are polymer blends cranprising a thermoplastic continuous phase in combination with a discontinuous vulcanized or unvulcanized elastomeric phase, which in the latter case could also be co-continuous. 

---