Structure and morphology of polycarbonate synthesized by solid state polycondensation
TL;DR: In this paper, solid state polycondensation (SSP) crystallizes polycarbonate in an orthorhombic configuration with a = 12.1 A, b = 10.5 A and c = 22.0 A.
About: This article is published in Polymer.The article was published on 1994-08-01. It has received 19 citations till now. The article focuses on the topics: Lamellar structure & Polycarbonate.
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TL;DR: In this article, a copolymer, poly(ethylene terephthalate- co-bisphenol A carbonate) was synthesized by simultaneous solid state polymerization and ester-carbonate interchange reaction between the oligomers of PET and PC.
10 citations
Patent•
11 Apr 1997TL;DR: In this paper, a process of forming a polycarbonate comprises providing a reaction mixture of at least one poly-carbonate-forming monomer and carbon dioxide; and then reacting the poly-carbonate-formating monomer with carbon dioxide in the reaction mixture to form the poly carbonate, which is then rendered useful for solid state polymerization.
Abstract: A process of forming a polycarbonate comprises providing a reaction mixture of at least one polycarbonate-forming monomer and carbon dioxide; and then reacting the polycarbonate-forming monomer and carbon dioxide in the reaction mixture to form the polycarbonate. In one embodiment, the polycarbonate is present in a condensate, and the process further comprises removing carbon dioxide from the reaction mixture; and then collecting the condensate from the reaction mixture. Moreover, uncrystallized polycarbonate may be treated with carbon dioxide to form crystalline polycarbonate. The crystalline polycarbonate is then rendered useful for solid state polymerization.
6 citations
TL;DR: In this paper, a facile strategy to induce crystallization of polycarbonate (PC) through solvent casting method is provided. Pristine fullerene (C60) and PC-modified C60 nanoparticles are applied as nucleating agents for PC, and the crystallization behavior of PC nanocomposite films is controlled by solvent casting preparation conditions.
Abstract: This work provides a facile strategy to induce crystallization of polycarbonate (PC) through solvent casting method. Pristine fullerene (C60) and PC-modified C60 nanoparticles are applied as nucleating agents for PC, and the crystallization behavior of PC nanocomposite films is controlled by solvent casting preparation conditions. To investigate the relationship between crystallization behavior and mechanical properties of PC nanocomposite films, X-ray diffraction, differential scanning calorimetry, polarizing microscope and tensile tests are carried out. Pristine C60 can only induce the formation of bulk PC spherocrystals which have no help or even deteriorates the mechanical properties of PC/C60 nanocomposite films. By contrast, the PC-modified C60 achieves uniformly disperse in the matrix and induces the formation of microcrystalline structures. It is found that appropriate degree of crystallinity for the PC/modified C60 nanocomposite films can effectively improve the mechanical properties. Typically, the PC/0.50 wt%-modified C60 nanocomposite films prepared under 40 °C by tetrahydrofuran exhibits up to a 33% increment in tensile strength and 45% increment in Young’s modulus compared to neat PC films.
3 citations
01 Dec 2020
TL;DR: In this paper, the elastic constants of polycarbonate were measured for the purpose of obtaining fundamental data for X-ray stress measurement of amorphous polymer materials, and a simple and practical measurement method directly using the raw profile data was also discussed.
Abstract: In polymer materials, residual stress introduced during injection molding affects yield reduction due to deformation during molding and delayed fracture during operation, so the establishment of nondestructive stress evaluation of polymer products is desirable. The X-ray elastic constants of polycarbonate were measured for the purpose of obtaining fundamental data for X-ray stress measurement of amorphous polymer materials. The structural function was obtained from the diffraction data, and the strain measured by X-ray was determined from the shift of the first peak by the Q-space method. The peak position was determined using the pseudo-Voigt function approximation method and the diffraction line width method. The Young’s modulus measured by X-ray obtained by the diffraction line width method was close to the mechanical value. Although these values varied widely, they changed depending on the peak ratio. A simple and practical measurement method directly using the raw profile data was also discussed. The Young’s modulus determined by the diffraction line width method decreased with increasing peak ratio. On the other hand, the values determined by the pseudo-Voigt method were almost constant, irrespective of the peak ratio. The strain calculated by the line width method was determined more accurately than that by the pseudo-Voigt method.
2 citations
Patent•
21 Oct 1998TL;DR: In this paper, a method for preparing polyesters by direct esterification, transesterification, melt acidolysis polymerization, and acid halide polymerization is presented.
Abstract: The present invention provides processes for preparing polyesters. The processes include (a) providing a polymerization medium comprising carbon dioxide, (b) contacting a monomer capable of forming a polyester polymer with the polymerization medium, and (c) polymerizing the monomer in the polymerization medium. The processes of the present invention include preparing polyesters by direct esterification polymerization, transesterification polymerization, melt acidolysis polymerization and acid halide polymerization. As a further aspect, the present invention provides a method of separating the polyester produced from the polymerization medium. Polyester polymers prepared according to the methods of the present invention are also provided.
2 citations
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TL;DR: In this article, the mechanism of action of organic nucleating agents such as sodium benzoate and its derived salts completely differs from the generally accepted model, at least in the case of polyesters.
Abstract: Several attempts1–5 have been made to control the rate of crystallization and the morphology by the addition of very finely-divided substances which promote abundant nucleation. However, these studies have mostly been carried out on an empirical basis and, except in a few cases (self-seeding6, epitaxy2–5), the mechanism of action of these nucleating agents is poorly understood despite several attempts at modelling1,2. This is particularly so in the case of most technical nucleating agents such as mica, talc and organic salts. We report here that the mechanism of action of organic nucleating agents such as sodium benzoate and its derived salts completely differs from the generally accepted model, at least in the case of polyesters. The nucleating agent reacts as a true chemical reagent with the molten macromolecules and produces ionic end groups which constitute the true nucleating species.
122 citations
TL;DR: In this paper, the authors show that polycarbonate from 4,4′-dihydroxydiphenyl-2,2-propan has a high shear strength.
Abstract: Es wird gezeigt, das das Polycarbonat aus 4,4′-Dihydroxydiphenyl-2,2-propan monoklin in der Raumgruppe Cs2 mit je 4 Ketten in der Gitterzelle, das Polycarbonat aus 4,4′-Dihydroxydiphenylsulfid und das aus 4,4′-Dihydroxydiphenylmethan dagegen rhombisch in der Raumgrupe C2v9 mit je 2 Ketten in der Gitterzelle kristallisiert. Die Faseridentitatsperiode umfast in allen drei Substanzen jeweils zwei monomere Einheiten, so das je 8 bzw. je 4 monomere Einheiten in der Gitterzelle liegen. Die Kristalldichten sind 1,315 g/ccm fur das Polycarbonat aus 4,4′-Dihydroxydiphenyl-2,2-propan, 1,50 g/ccm fur das Polycarbonat aus 4,4′-Dihydroxydiphenylsulfid und 1,303 g/ccm fur das Polycarbonat aus 4,4′-Dihydroxydiphenylmethan. Die Faseridentitatsperioden der drei betrachteten Polycarbonate sind um ca. 15% bis 20% gegenuber ihrer theoretischen Maximallange bei voll ausgestreckten Ketten verkurzt. Dementsprechend betragt der Kristall-Elastizitatsmodul in Kettenrichtung ca. 450 bis 600 kp/mm2. Die betrachteten Kristallstrukturen enthalten keinerlei Gleitebenen, so das die Kristallbereiche eine hohe Scherfestigkeit besitzen. Die geringe Kristallisationstendenz des Polycarbonates aus 4,4′-Dihydroxydiphenyl-2,2-propan findet durch die Kristallstruktur eine plausible, zwanglose Erklarung.
The polycarbonate from 4,4′-dihydroxydiphenyl-2,2-propane crystallizes monoclinically in the space group Cs2 with four chains each in the lattice cell, but the polycarbonate from 4,4′-dihydroxydiphenyl sulfide and from 4,4′-dihydroxydiphenyl methane crystallizes orthorhombically in the space group C2v9 with two chains each in the lattice cell. In all three substances, the fibre identity period always comprises two monomeric units, so that always eight and always four monomeric units, respectively, are located in the lattice cell. The crystal densities are 1.315 g./ccm. for the polycarbonate from 4,4′-dihydroxydiphenyl-2,2-propane, 1.50 g./ccm. for the polycarbonate from 4,4′-dihydroxydiphenyl sulfide, and 1.303 g./ccm. for the polycarbonate from 4,4′-dihydroxydiphenyl methane. The fibre identity period of the three substances, as compared with their theoretical maximum length in the case of fully stretched chains, has been shortened by 15 per cent to 20 per cent. Accordingly, the crystal elasticity modulus in the direction of the chain only amounts to about 450 to 600 kp./mm2. The crystal structures considered do not contain any glide planes, so that the crystal domains possess a high shear strength. The low crystallization tendency of the polycarbonate from 4,4′-dihydroxydiphenyl-2,2-propane is easily and plausibly accounted for by its crystal structure.
73 citations
TL;DR: The rate of spherulite growth, measured by means of polarisation microscope, depends on the chemical structure of the polycarbonate as mentioned in this paper, which is a relatively high tendency to crystallize.
Abstract: Polycarbonate auf der Basis 4,4′-Dioxy-diphenyl-2,2-propan, 4,4′-Dioxy-diphenylmethan und 4,4′-Dioxy-diphenyl-sulfid kristallisieren mit athermischer Keimbildung aus der Schmelze spharolithisch. Es wurden verschiedene morphologische Strukturen beobachtet.
Die lichtmikroskopische Bestimmung der Spharolith-Wachstumsgeschwindigkeit last eine unterschiedliche Kristallisationsneigung der betrachteten aromatischen Polycarbonate erkennen. Danach zeigt das Polycarbonat auf Basis 4,4′-Dioxy-diphenyl-2,2-propan ein stark gehemmtes und verzogertes Kristallisationsverhalten, wahrend die Polycarbonate auf Basis 4,4′-Dioxy-diphenyl-methan und 4,4′-Dioxy-diphenylsulfid als relative kristallisationsfreudig zu bezeichnen sind. Als Ursache fur das unterschiedliche Kristallisationsverhalten wird der verschiedenartige molekular Aufbau diskutiert.
Polycarbonates from 4,4′-Dioxy-diphenyl-2,2-propan, 4,4′-Dioxy-diphenylmethan, and 4,4′-Dioxy-diphenyl-sulfid crystallize from the melt with spherulitic structure and athermal nucleation. Depending on crystallization conditions different morphological textures were observed.
The rate of spherulite growth, measured by means of polarisation microscope, depends on the chemical structure of the polycarbonate. The crystallization of polycarbonates from 4,4′-Dioxy-diphenyl-2,2-propan is hindered by the spacefilling isopropyl-group. On the other hand, polycarbonates from 4,4′-Dioxy-diphenyl-methan and 4,4′-Dioxy-diphenyl-sulfid have a relatively high tendency to crystallisation.
38 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