Structure, growth and morphology of polyphenylene sulphide
TL;DR: The crystallinity, particle size and morphology of polyphenylene sulphide synthesized from 1, 4-dibromobenzene and sodium sulphide have been investigated by X-ray diffraction and scanning electron microscopy as discussed by the authors.
Abstract: The crystallinity, particle size and morphology of polyphenylene sulphide synthesized from 1, 4-dibromobenzene and sodium sulphide have been investigated by X-ray diffraction and scanning electron microscopy. It was found that the crystallinity increased from 62 to 68% with an increase in reaction time. A reordering of crystalline structure with increase of reaction time was also noted. The particle size growth was slower as compared to the reaction rate and the distribution was very sharp. The results are compared with those for polyphenylene sulphide obtained from 1, 4-dichlorobenzene and sodium sulphide.
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TL;DR: The first known report of its synthesis was by Grenvesse in 1898 [1] and interest in the synthesis of PPS only began in 1948 when Macallum 121 described the preparation of phenylene sulfide polymers by the melt reaction of p-dichlorobenzene with sodium carbonate and sulfur as mentioned in this paper.
Abstract: Among the various high temperature polymers, those based on aromatic units, such as poly(2, 6-dimethylphenylene oxide) (PPO), poly(pheny1ene sulfide) (PPS), poly(ether ether ketone) (PEEK), and poly(ether sulfone) (PES), have attracted much attention in the last few years due to their good thermal and chemical resistance. One of these polymers, PPS, is also an important high strength/high temperature engineering thermoplastic that is finding increasing use in technological applications such as molding resins, fibers, and matrices for thermoplastic composites. PPS consists of para-phenylene units alternating with sulfide linkages. The first known report of its synthesis was by Grenvesse in 1898 [1]. However, interest in the synthesis of PPS only began in 1948 when Macallum 121 described the preparation of phenylene sulfide polymers by the melt reaction of p-dichlorobenzene with sodium carbonate and sulfur. Further investigation on the synthesis of PPS by Lenz and coworkers [3–5], and later by Edmo...
89 citations
TL;DR: The cellular microenvironment can be engineered to enhance the ability of cells to become transfected and that through understanding the mechanisms by which the ECM affects non-viral gene transfer better materials and transfection protocols can be realized.
36 citations
TL;DR: In this article, a polyethylene oxide containing high concentrations of Cu(ll) chloride has been studied as a function of temperature and a new hexagonal type structure with unit cell dimensions of a = 6.52 and c = 19 is seen to occur for high concentration of the copper chloride.
30 citations
TL;DR: In this article, the growth of polypyrrole (PPy) on crystalline poly(ethylene oxide)-ferric chloride complexes has been investigated by X-ray diffraction, optical and scanning electron microscopy.
25 citations
TL;DR: The structure, growth and morphology of calcium sulphate prepared in situ of a polymer has been investigated using polyethylene oxide as the growth medium as mentioned in this paper, and the results have been explained on the basis of polymer mediated crystallization and large interaction between the filler and the matrix.
Abstract: The structure, growth and morphology of calcium sulphate prepared in situ of a polymer has been investigated using polyethylene oxide as the growth medium The structure was predominantly the dihydrate type with monoclinic configuration for these samples as compared to the anhydrite type with orthorhombic structure obtained in commercial samples The crystal morphology consisted of sharp needle shape, having aspect ratio of more than 10 The concentration of the polymer used had a profound effect on the crystal size and its distribution The size distribution became narrow and the average crystal size reduced with the increase of polymer concentration Highly oriented crystals could be obtained with application of, small shearing force on the samples These results have been explained on the basis of polymer mediated crystallization and large interaction between the filler and the matrix © 1998 Chapman & Hall
23 citations
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Book•
01 Jan 2002TL;DR: In this article, the authors present a self-contained treatment of polymer crystallization, focusing on the thermodynamics and physical properties that accompany the morphological and structural changes that occur when a collection of molecules of very high molecular weight are transformed from one state to another.
Abstract: First published in 2002, from an original 1964 edition, in the Crystallization of Polymers, 2nd edition Leo Mandelkern provides a self-contained treatment of polymer crystallization. All classes of macromolecules are included and the approach is through the basic disciplines of chemistry and physics. The book discusses the thermodynamics and physical properties that accompany the morphological and structural changes that occur when a collection of molecules of very high molecular weight are transformed from one state to another. Volume 1 is a presentation of the equilibrium concepts that serve as a basis for the subsequent volumes. In this volume the author shows that knowledge of the equilibrium requirements is vital to understanding all aspects of the polymer crystallization process, and the final state that eventually evolves. This book will be an invaluable reference work for all chemists, physicists and materials scientists who work in the area of polymer crystallization.
1,206 citations
TL;DR: Most organic polymeric materials melt below 200 °C and most of them begin to degrade rapidly at temperatures only slightly above 200°G. Thermally stable polymers are those which will withstand much higher temperatures without loss of strength or change of structure as mentioned in this paper.
Abstract: Most organic polymeric materials melt below 200 °C and most of them begin to degrade rapidly at temperatures only slightly above 200°G. Thermally stable polymers are generally considered to be those which will withstand much higher temperatures without loss of strength or change of structure. In general we expect these materials to withstand at least 300°C in air and up to 500°C or higher in inert atmospheres. Polymers which show these properties are usually highly aromatic in structure, often with heterocyclic units, high melting, sometimes infusible and usually with low solubility in all solvents. This makes their fabrication very difficult and as a consequence limits their usefulness.
587 citations
Book•
01 Jan 1974
231 citations
"Structure, growth and morphology of..." refers background in this paper
...600 termination rates [10], the type of polymerization reaction [11] (condensation, addition, etc)....
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TL;DR: In this paper, strong electron acceptors (AsF5, SbF5) are applied to poly(thio 2,8,dibenzothiophenediyl) to form conducting complexes with p-type electronic conductivities up to 3 S/cm.
Abstract: Poly(p‐phenylene) sulfide, poly(m‐phenylene) sulfide, and the newly synthesized polymer poly(thio‐2,8‐dibenzothiophenediyl) have been treated with strong electron acceptors (AsF5, SbF5) to form conducting complexes with p‐type electronic conductivities up to 3 S/cm. Near IR to UV absorption spectra and temperature‐dependent conductivity measurements suggest a localization of charge carriers even at high doping levels. Elemental analysis and IR spectroscopy demonstrate that heavy exposure to AsF5 causes substantial changes in the backbone structure of these polymers. The dopant appears to predominantly induce the formation of carbon–carbon bonds bridging the sulfur linkages to form thiophene rings. This chemical modification enhances the conductivity of the complex and, in the case of poly(m‐phenylene), is shown to be an actual prerequisite for achieving high conductivity.
161 citations
TL;DR: In this paper, a variety of new developments in molding methods and long term properties of polyphenylene sulfide are described along with a comprehensive tabulation of mechanical, factional, and electrical properties of various filled and unfilled compositions.
Abstract: Polyphenylene sulfide is a new engineering plastic characterized by a unique combination of useful environmental, mechanical, and flame resistant properties. This paper presents a variety of new developments in molding methods and long term properties of polyphenylene sulfide. Optimum conditions for fabrication by injection molding, compression molding, and free sintering techniques are described along with a comprehensive tabulation of mechanical, factional, and electrical properties of various filled and unfilled compositions. The effect of injection molding conditions and post-treatments, such as annealing, on mechanical behavior is discussed. Long term stability of molded specimens of the polymer to a variety of chemical environments as well as oven aging studies are reported. The significance of these properties is illustrated by a discussion emphasizing new applications for various compositions based on polyphenylene sulfide.
98 citations