Polymers practical implications

Rate considerations have enormous practical implications to anyone working with polymers. As an example, it may be possible to make an incredible new polymer, but would we be able to profitably commercialize this super new polymer if its polymerization took weeks, months, or even years to occur Rather obviously, the answer is no . Therefore, we must study the rates of reactions in an effort to understand how to produce materials in the time scales we have at our disposal. The study of kinetics provides us with the tools and the knowledge necessary to understand the rates of the polymerization reactions that are important to us. Kinetic studies allow us to understand the energetic considerations necessary for a reaction to progress. We also gain the tools to propose mechanisms that describe how a reaction actually occurs at the molecular level. 

For polyacrylamides, as a function of polymer ionicity, the presence of calcium induces a maximum in intrinsic viscosity and a minimum in adsorption density on siliceous minerals. This holds important practical implications in EOR since an optimal polymer ionicity can be selected according to field conditions. 

These differences in the effect of polymers on various flocculation responses have important theoretical and practical implications and can be explained in terms of various characteristics of floes and floc-aggregates. Polymer adsorption or attachment of particles to polymer can occur in any number of configurations, and as a result the aggregation of particles also can take place in many ways, leading to different floe and suspension structures which will respond differently to different tests. 

Although several peroxidase enzymes obtained from plant, animal, and microbial sources have been investigated for their ability to catalyze the removal of aromatic compounds from wastewaters, the majority of studies have focused on using HRP. In particular, it has been shown HRP can transform phenol, chlorophenols, methoxyphenols, methylphenols, amino-phenols, resorcinols, and various binuclear phenols [7], HRP was also used for the treatment of contaminants including anilines, hydroxyquinoline, and arylamine carcinogens such as benzidines and naphthylamines [7,8]. In addition, it has been shown that HRP has the ability to induce the formation of mixed polymers resulting in the removal of some compounds that are either poorly acted upon or not directly acted upon by peroxidase [7], This phenomenon, termed coprecipitation or copolymerization, has important practical implications for wastewaters that usually contain many different pollutants. This principle was demonstrated when it was observed that polychlorinated biphenyls (PCBs) could be removed from solution through coprecipitation with phenols [20]. However, this particular application of HRP does not appear to have been pursued in any subsequent research. 

Linear amino polymers containing basic nitrogen atoms are critically reviewed with regard to their synthesis, protonation and complex formation in solution with metal ions. Cross linked resins having essentially the same structure as linear polymers, are also mentioned. As far as the proto-nation is concerned, special care has been given to thermodynamic aspects, and to the most probable protonation mechanism. Complexing abilities of these polymers have been evaluated through stability constants and spectroscopic parameters. Practical implications of the properties have been considered. 

When aluminum borate whiskers were incorporated in SAN/PA-6 blends, the whisker, due to acid/based interaction had a better affinity to PA-6 than to SAN and for this reason they ended up in residence in the polyamide phase. A similar principle was used to obtain a conductive blend by compounding PA, PP and carbon black. Carbon black has a better affinity to polyamide and thus it prefers to reside in the polyamide phase or in the interphase formed between two immiscible polymers. Even when carbon black is added initially to polypropylene, it still transfers to the polyamide phase. This migration and preferential location of carbon black is not only an interesting scientific principle but it also has important practical implications. For the purpose of conductivity, a certain threshold concentration of carbon black is required to enable percolation and this threshold concentration is substantially lower if the carbon black settles in only one phase. This phase be-... 

The synthesis of polymers and oligomers that mimic the complex constructions and notable biological properties of proteins is crucial research with both fundamental and practical implications. Therefore, considerable work has gone into designing polymers, which mimic important physico-chemical properties, such as the existence of both cationic and hydrophobic groups, of naturally occurring AMP [11-14],... 

Turbulent drag reduction in homogeneous flows by polymer or surfactant additives is a striking phenomenon with both theoretical and practical implications. On the theoretical side, it remains a challenge to fully understand the drag reduction mechanism and the interaction details between DRAs and the turbulent flow field. New methods, especially computational ones, have been developed to solve this problem, such as direct numerical simulations and stochastic simulations. On the application... 

Physical aging effects have practical implications and need to be considered when assessing the long-term stabihty of polymers and polymer-polymer mixtures. This chapter focuses on a discussion of the effect of blending on physical aging and gives a review of the different experimental methods that can be used to compare aging rates in blends to those of the individual components. 

Practical implication of plastic recycling in form of polymer mixtures delays and aggravates problem of waste accumulation rather than solves it... 

Polymer melt devolatilisation has been the subject of extensive theoretical analysis [19], resulting in important practical implications for the preparation of filled polymer composites, with optimum particle wet-out and freedom from volatile matter. 

A new electroactive conductive polymer was synthesized by electrochemical polymerization of (31) in propylene carbonate [62]. A pseudocrown ether structure (32) was expected to occur by the template effect, but the real structure was not clear. The results of the above polymers bearing etheric lateral groups should have practical implications for the design of selective electrode, charge-controllable membrane and drug-release devices. 

Many of the above effects are empirical. Polymer physicists are now trying to understand and predict certain properties. The interface between addi-tive/polymer or polymer blends has received attention. One problem is how thick this interface has to be—several atoms or several thousand atoms thick Another problem is how energy is absorbed during fracture. Theoretical calculations have not been able to predict why some polymers are more difficult to fracture than others (this is not quite the same as saying that an amorphous polymer will incur brittle fracture below its Tg). The diffusion of polymer molecules at molten interfaces is another problem which has practical implications—crack annealing and fusion/joining of preformed parts. 

From the solar spectrum passing through the earth s atmosphere, it is evident that no radiation with a wavelength < 300 nm is transmitted by the atmosphere. This has important practical implications in that the number and type of photochemical reactions which may occur are thereby severely restricted, in comparison to the case when polymer samples are exposed to radiation from UV radiation sources. Since the energy of (sun)light (E ) is inversely proportional to the wavelength, i.e. ... 

An alternative analysis of colloidal interaction and stability based on classical solution thermodynamics has been proposed independently by Hall (1972) and Ash etal. (1973) and the practical implications with particular interest in the effects of polymers and surfactants has been discussed by Pethica (1986). In this theory, the forces between particles are governed in a straightforward way by the adsorptions of the components of the system and their dependence of particle separation and chemical potentials (which are defined by the composition) according to the equation... 

A distinguishing feature of Pierre Gilles de Gennes contributions to polymer physics has been his application of new fundamental ideas to problems with practical implications. This paper deals with steric stabilization forces, an area where de Gennes has played an illuminating and stimulating role over the past several years. 

W, Schnabel, in Polymer Degradation - Principles and Practical implications , Hanser Publishers, Munich, 198 1, p. 98. 

Epitaxial Crystallization This aspect of crystallization deserves to be mentioned. Polymer-polymer epitaxy (209-210) involving mutual interactions between different macromolecules where crystallinity, crystal stmc-ture, lattice matching, molecular conformation and chemistry have been considered. The kinetics of epitaxial processes have been largely ignored despite their plausible significance in surface bonding that has practical implications. 

In addition to its practical importance, Tx has important theoretical implications for the understanding of the molecular origin of polymer mechanical behavior (3,4,6,35,42-45) and plays a central role in establishing the framework, mentioned above, which relates the properties of different polymers to each other (3 46.47). 

---