Chapter 1 - Polymer Properties

Rheology forms the fundamental basis of understanding the polymer chain dynamics in the field of polymer science where the outcomes play significant role in improving the processing of polymer melt and the final properties of polymer products. This review focuses on the influence of immiscible nanoparticles on the physical properties of polymers from the rheological point of view. To explain the viscoelastic behaviors of nanoparticle filled polymeric systems, the experimental studies which are limited to the linear regime of flow and deformation are considered under the scope of this article. In-depth rheological analysis of filled polymeric systems is crucial for the verification of material properties before the production of final products, and for its utilization on a larger scale. This allows efficient design of optimal equipment for processing which improves overall process economics. The rheological aspects such as viscosity, network formation and crosslinking, chain relaxation dynamics, and crystallization of polymers in presence of fillers, which are particularly important when determining the parameters for processing of nanoparticle filled polymeric systems, are studied. The processing parameters represent a key design element that have impact on development of unique products for desired application.

Uptil now it has not been possible to explain the different physical properties of amorphous polymers using a model based on a single conceptual scheme. In this paper, a phenomenological model is proposed which tries to explain the mechanical, optical and thermal properties (both thermal conductivity and expansivity) of amorphous polymers. The model has similarities with the composite model, proposed by the present authors, which has proved to be successful in interpreting the different physical properties of semicrystalline polymers. The present model considers the bulk form of the polymer as an aggregate of microscopic units possessing intrinsic physical properties. On drawing, the development of anisotropy in different physical properties is supposed to be due to the development of preferred orientation of these units. The development of the preferred orientation has been estimated directly from birefringence data. The agreement between the calculated and experimental values of the elastic modulus, thermal conductivity and thermal expansivity of PVC, PMMA and PS is found to be reasonable good.

This article shows the extent to which the entanglement of threadlike molecules can influence many of the properties of deformable polymers and of solutions of macromolecular substances. Thus, the molecular concept of entanglement leads to quantitative predictions of the dependence of the entanglement number on the nature of the polymer, its concentration, and extension. Experimental values of the relaxation modulus confirm these predictions for melts and solutions. The influence of entanglemnt on relaxation and flow processes leads to very simple relationships for the magnitudes of the structural viscosity and the shear stress at which the structural viscosity starts to become measurable. Osmotic pressures, light scattering intensities, and diffusion coefficients of concentrated solutions can be derived quantitatively from the conformational constraints due to entanglement. Entanglement is effective above a concentration at which the three‐dimensional coils fill the solution volume, and probably also at lower concentrations. At very high concentrations entangled structures may be formed which drastically reduce the number of possible conformations. The swelling and extension behavior of cross‐linked deformable polymers can be understood only if entanglement is taken into account.

The manipulation of a polymer’s properties without altering its chemical composition is a major challenge in polymer chemistry, materials science and engineering. Although variables such as chemical structure, branching, molecular weight and dispersity are routinely used to control the architecture and physical properties of polymers, little attention is given to the often profound effect of the breadth and shape of the molecular-weight distribution (MWD) on the properties of polymers. Synthetic strategies now make it possible to explore the importance of parameters such as skew and the higher moments of the MWD function beyond the average and standard deviation. In this Review, we describe early accounts of the effect of MWD shape on polymer properties; discuss synthetic strategies for controlling MWD shape; describe current endeavours to understand the influence of MWD shape on rheological and mechanical properties and phase behaviour; and provide insight into the future of using MWDs in the design of polymeric materials. Controlling polymerization is required to fully understand and tune the function of a polymer. Alongside variables such as dispersity, molecular weight and chemical composition, the shape of the molecular-weight distribution has substantial influence on polymer properties. In this Review, we discuss methods to systematically control the shape of a polymer’s molecular-weight distribution, as well as explore the profound effects of shape on polymer properties.

Stereoregular polymers constitute a large class of macromolecular compounds that are endowed with many interesting and valuable properties. The natural ones are of vital importance. The properties that these polymers possess are determined in large part by their steric regularity. The essential role of stereochemistry in determining the physical and chemical properties of chemical compounds was envisaged by Wislicenus (1) more than one hundred years ago. That this applies to high as well as to low molecular weight compounds was recognized early during the development of macromolecular science. In the late twenties Meyer and Mark (2,3) interpreted the differences between natural rubber and gutta-percha by suggesting that the former represents the eis- and the latter the trans-form of 1,4-polyisoprene, and Staudinger proposed stereoirregularity as the cause of the non-crystallizability of polyindene (4,5), polystyrene (5) and polyvinylacetate (5). At that time researchers were gradually beginning to realize that all organic polymers found in nature and containing sites of stereoisomerism were stereoregular. The development in the understanding of the structure of various natural polymers has been described by Meyer (6). Thus it must have become obvious that stereoregularity is an essential condition in order for these natural polymers to carry out their specific biologic functions. However, fundamental studies on the influence of stereochemistry on the physical and chemical properties of polymers started only in the late forties, when the first stereoregular polymers were synthesized from monomers non containing stereoisomerism sites. Great impetus to developments in this area was given by the first synthesis of a highly stereoregular polypropylene by Natta and his group in 1955 (7). This originated a large interest in the synthesis and the study of other stereoregular polymers, thus forming the basis for the remarkable progresses achieved in this area in the last 20 years. From this development it clearly emerged that stereochemistry strongly influences the reactivity, the conformational equilibria and many physical properties of polymers in dilute solution and in the melt. For chemically regular polymers, stereochemistry determines the type of crystal structure and the degree of crystallinity, and thus determines the properties of these polymers in the solid state. Therefore, it is not surprising that, in some cases (e.g. polypropylene) stereochemistry may even determine the success of the industrial application of a polymeric product. The relevance of synthetic stereoregular polymers is by no means limited to the study and applications of the relationships between polymer stereochemistry and properties. Progress in many other areas of polymer science has been made possible or has been accelerated by studies on stereoregular synthetic polymers. In particular, significant advances in the understanding of the mechanism of various polymerization processes have been achieved through the efforts made to elucidate the factors that determine the formation of stereoregular polymers. Furthermore, some factors influencing the mode of crystallization of the polymer chains and the morphology of the polymers have been clarified by the investigation of the large number of stereoregular polymers which have been synthesized.

Chapter 10 - Optical Properties

Chapter 6 - Hygienic Design of Open Food Processing Equipment

High performance polymers for oil and gas applications

Effect of chemical structure on thermo-mechanical properties of epoxy polymers: Comparison of accelerated ReaxFF simulations and experiments

Porphyran, sulfated polysaccharide, is derived from the cell wall and intercellular regions of Porphyra and known to be closely related to agarose in its basic structure, whereas it is very different in terms of having L-galactose-6-sulfate. Besides of various physiological effects, it is having wide pharmaceutical applications. Its structure-related gelling and emulsification properties have given birth to a new polymer in polymeric science. Porphyran uses are based on their unique properties to form strong gels after desulfation in an aqueous solution. This gel results from peculiar regular chemical structures, specific ordered molecular conformations, and aggregations. Now a days, new methodologies and instruments have provided a more accurate view of the relationships between the chemical structure and the gelling characteristics of these complex hybrid and heterogeneous polysaccharides. NMR is the single most powerful technique for solving the structures of intact polysaccharides. Developments in the NMR render the determination of structural distribution of this galactan more accessible. Such techniques also yield new information on the aggregate formation of these sulfated polysaccharides. These and other data question the existence of the generally assumed intertwined double helical conformations of these galactans during gel formation. Currently, porphyran availability is not known because of several problems such as its high molecular weight and viscosity that are suppressing its growth in world market. Hence, world market needs development of this novel compound to improve its pharmaceutical applications though this is an area of algal utilization that demands more research. How to Cite this Article Pubmed Style Bhatia S, Namdeo AG, Nanda S. Effecting the Gelling and Emulsifying Properties of a Natural SRP. 2010; 1(1): 86-92. doi:10.4103/0975-8453.59517 Web Style Bhatia S, Namdeo AG, Nanda S. Effecting the Gelling and Emulsifying Properties of a Natural http://www.sysrevpharm.org/?mno=302644635 [Access: March 28, 2021]. doi:10.4103/0975-8453.59517 AMA (American Medical Association) Style Bhatia S, Namdeo AG, Nanda S. Effecting the Gelling and Emulsifying Properties of a Natural SRP. 2010; 1(1): 86-92. doi:10.4103/0975-8453.59517 Vancouver/ICMJE Style Bhatia S, Namdeo AG, Nanda S. Effecting the Gelling and Emulsifying Properties of a Natural SRP. (2010), [cited March 28, 2021]; 1(1): 86-92. doi:10.4103/0975-8453.59517 Harvard Style Bhatia S, Namdeo AG, Nanda S (2010) Effecting the Gelling and Emulsifying Properties of a Natural SRP, 1 (1), 86-92. doi:10.4103/0975-8453.59517 Turabian Style Bhatia S, Namdeo AG, Nanda S. 2010. Effecting the Gelling and Emulsifying Properties of a Natural Systematic Reviews in Pharmacy, 1 (1), 86-92. doi:10.4103/0975-8453.59517 Chicago Style Bhatia S, Namdeo AG, Nanda S. Factors Effecting the Gelling and Emulsifying Properties of a Natural Polymer. Systematic Reviews in Pharmacy 1 (2010), 86-92. doi:10.4103/0975-8453.59517 MLA (The Modern Language Association) Style Bhatia S, Namdeo AG, Nanda S. Factors Effecting the Gelling and Emulsifying Properties of a Natural Polymer. Systematic Reviews in Pharmacy 1.1 (2010), 86-92. Print. doi:10.4103/0975-8453.59517 APA (American Psychological Association) Style Bhatia S, Namdeo AG, Nanda S (2010) Effecting the Gelling and Emulsifying Properties of a Natural Systematic Reviews in Pharmacy, 1 (1), 86-92. doi:10.4103/0975-8453.59517

The IUPAC study ‘‘Structure and Properties of Linear and Cross-Linked Structural Polyvinylchloride Foams’’ (IUPAC no. 2003-038-4-400) of the IUPAC Subcommittee ‘‘Structure and Properties of Commercial Polymers’’ elucidates the mechanical properties of Polyvinylchloride foams. In order to predict the mechanical properties of polymer foams several simplified models were developed which take into account the density and stiffness of the bulk material, but do not apply any morphological information. Previous results on Polyvinylchloride foams indicate that the cubic model of Gibson and Ashby is not suitable to predict their compressive modulus. In this article, we discuss several alternatives for the prediction of the mechanical properties. In particular, a novel approach is presented in order to transfer cell morphological data obtained by computer tomography to realistic finite element meshes for numerical simulations. This approach allows to take into account the statistical character of the foam morphology and can be applied to predict the mechanical properties of foams. First, a computer tomography analysis was performed to determine the size distribution of the polymer foams using a nondestructive technique. The computer tomography information was applied to build finite element meshes using a tessellation of modified Kelvin cell units or truncated octahedra of various cell sizes. Then finite element simulations were performed using these meshes in order to predict the compressive behavior of polymer foams. The results of the numerical simulations were in a good agreement with those of experimental data. In conclusion, the mechanical properties of cellular polymers can be adequately predicted by taking into account the inhomogeneous foam structure, in particular the cell size distribution.

This authoritative, widely cited book has been used all over the world. The fourth edition incorporates the latest developments in the field while maintaining the core objectives of previous editions: to correlate properties with chemical structure and to describe methods that permit the estimation and prediction of numerical properties from chemical structure, i.e. nearly all properties of the solid, liquid, and dissolved states of polymers. This title extends coverage of critical topics such as electrical and magnetic properties, rheological properties of polymer melts, and environmental behavior and failure. It discusses liquid crystalline polymers across chapters 6, 15, and 16 for greater breadth and depth of coverage. It increases the number of supporting illustrations from approximately 250 (in the previous edition) to more than 400 to further aid in visual understanding.

Environmentally induced colour change during natural degradation of selected polymers

3 - Effect of moisture on elastic and viscoelastic properties of fiber reinforced plastics: Retrospective and current trends

The molecular relaxations in polymeric systems have aroused great interest among polymer scientists during the last decades because these phenomena have profound effects upon many important properties of polymers (e.g., upon mechanical behavior, solid-state reactivity, diffusion, melt rheology, and solution properties).