Polymer blend, advantages

Oligomeric Flame Retardants. There are several oligomeric flame retardants. The principal advantage claimed for these materials is their resistance to bloom and plate-out. In some cases they are used at levels high enough that the resulting flame-retarded resia should properly be viewed as a polymer blend or alloy. AH of the available oligomeric flame retardants are brominated (Table 6). 

Although the concept of polymer blends is sometimes a route for a voiding the development of new polymers, it often has been an integral part of the utiliza tion of new polymer chemistry, eg, the commercial success of PPO hinged on the advantages of its blends with PS. 

PBAs are designed explicitly to meet the needs of specific applications on the basis of their property-processing-cost performances. One polymer is incorporated into the matrix of other polymers to impart specific characteristics as per the requirement along with the appropriate compatibilizer to ensure stress transfer in between phases. The polymer blend constituents and composition must, therefore, be selected on the basis of the compensation of properties, considering the advantages and disadvantages associated with each phase. Table 12 indicates some of the components used as modifiers. 

Block copolymers possess unique and novel properties for industrial applications. During the past 20 years, they have sparked much interest, and several of them have been commercialized and are available on the market. The most common uses of block copolymers are as thermoplastic elastomers, toughened thermoplastic resins, membranes, polymer blends, and surfactants. From a chemist s point of view, the most important advantage of block copolymers is the wide variability of their chemical structure. By choice of the repeating unit and the length and structure of both polymer blocks, a whole range of properties can be adjusted. 

The heat distortion temperature of impact-resistant polystyrene may also be improved by polymer blends. Those of impact-resistant polystyrene with poly-2,5-dimethylphenylene-1,4-oxide (PPO) are particularly interesting (90). Polystyrene and PPO are molecularly compatible and mixtures of them have glass transition temperatures which vary virtually linearly with composition. A further advantage of these compositions which should not be under-estimated is their better flame resistance. 

Furthermore, another advantage of nanofillers is not only to reinforce the rubber matrix but also to impart a number of other properties such as barrier properties, flammability resistance, electrical/electronic and membrane properties, and polymer blend compatibility. In spite of tremendous research activities in the field of polymer nanocomposites during the last two decades, elastomeric nanocomposites... 

Tlie use of polymer blends has been a very important approach in the development of new materials for evolving applications, as it is less costly than developing new polymers. The compatibility of poly(vinylidene fluoride) (PVDF) with various polymers has been comprehensively evaluated and has led to useful applications in coatings and films. Poly(methyl methacrylate) has been the most studied compatible polymer with PVDF owing to cost and performance advantages. Other acrylic polymers such as poly(ethyl methacrylate), poly(methyl acrylate), and poly(ethyl acrylate) have also been found to be compatible with PVDF. ... 

The crosslinking kinetics and the final state of cure are commonly studied with the aid of rheometers. NMR relaxation experiments can offer several advantages for the characterisation of the crosslinking kinetics in complex materials because of high method selectivity with respect to the rubbery chains/phases in polymer blends, filled and oil extended rubbers. 

C NOE spectroscopy under MAS was used for probing polymer miscibility in polymer blends, polystyrene/polyvinyl methyl ether (PS/PVME) [42], This study takes advantage of the fact that crosspeaks appear only between spins that are neighbours of each other,... 

Water is the main ingredient of the continuous phase of most emulsion paints. It is also used alone, or blended with alcohols or ether-alcohols, to dissolve water-soluble resins. Any type of resin can be made water-soluble by incorporating sufficient carboxylic groups into the polymer. The advantages of water as a solvent are its availability, cheapness, lack of smell, nontoxicity, and nonflammability. However, it is not an ideal paint solvent because of its limited miscibility with other organic solvents, and because film formers designed to be dissolved or dispersed in water usually remain permanently sensitive to water. 

---