Structural aspects of suspension poly(vinyl chloride): The thermal aspects of rigid suspension PVC

Scherrenberg, Rolf; Reynaers, Harry; Gondard, C.; Steeman, P. A. M.

doi:10.1002/polb.1994.090320114

Cited by 12 publications

(9 citation statements)

References 26 publications

(7 reference statements)

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“…Nevertheless, a converse opinion prevails in other works. At a given melt temperature, Scherrenberg [25] has obtained similar melting levels for heat-treated dryblends and compression molded samples. This trend has also been confirmed by Teh [19], who proposed an alternative method for assessing gelation with DSC, arguing that the conventional method cannot differentiate the crystallites that contribute to the formation of the three-dimensional network from those that do not.…”

Section: Fig 3 Waxs Patterns Of Sheets Milled At Two Extreme Tempermentioning

confidence: 85%

U‐PVC gelation level assessment, part 1: Comparison of different techniques

Fillot

Hajji

Gauthier

et al. 2006

Vinyl Additive Technology

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Several different gelation assessment methods such as differential scanning calorimetry, capillary rheometry, solvent absorption, wide angle x-ray scattering, transmission electron microscopy, and atomic force microscopy were applied to a typical PVC window profile formulation subjected to various thermomechanical histories. Shear applied during the process could be decomposed into two components: (i) a thermal component corresponding to the self-heating that was generated and (ii) a "mechanical" component associated with a "pure" shearing action deprived of any thermal aspect. Shear sensitivity of the above-mentioned gelation assessment techniques was evaluated by considering both aspects. Gelation levels established by differential scanning calorimetry and capillary rheometry were especially compared, thus allowing a comparison of the two physical aspects evidenced by each technique, i.e., crystallite melting and macromolecular network development. It appeared that as soon as the PVC particulate structure had been fragmented into micronic entities (primary particles) the gelation process was governed mainly by the thermal aspect, i.e., crystallite melting. J. VINYL ADDIT. TECHNOL., 12:98 -107, 2006.

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Section: Fig 3 Waxs Patterns Of Sheets Milled At Two Extreme Tempermentioning

confidence: 85%

U‐PVC gelation level assessment, part 1: Comparison of different techniques

Fillot

Hajji

Gauthier

et al. 2006

Vinyl Additive Technology

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“…This melting behavior can be explained by recrystallizationremelting concept. 18 T m1 is considered to be characteristic of the melting of the crystals formed at the given crystallization temperature. T m2 results from the melting of crystals formed by recrystallization of imperfect crystals during the reheating stage.…”

Section: Resultsmentioning

confidence: 99%

Effect of Silica Nanoparticle on the Quiescent and the Shear Induced Crystallization Behaviors of Poly(trimethylene terephthalate)

Nam

Shim

Kim

et al. 2004

Polym J

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ABSTRACT:The isothermal crystallization behavior of poly(trimetylene terephthalate) (PTT) containing silica nanoparticles was investigated. The addition of silica nanoparticles increased the crystallization temperature of PTT by 20 C and notably decreased the size of the crystals. Higher silica nanoparticle content led to greater depression of equilibrium melting temperature. Quiescent isothermal crystallization in DSC capsule showed that silica nanoparticles acted as a nucleating agent for PTT and decreased the half time for crystallization. In the case of PTT containing silica nanoparticles 1 and 2 wt %, however, little difference in the crystallization behavior was noticeable, suggesting that the silica content of 1 wt % is the critical level for nucleating. Isothermal crystallization under dynamic shear showed similar crystallization behavior with quiescent crystallization. In addition, higher shear rate accelerates the crystallization rate of PTT. However, X-Ray diffraction result revealed that the content of silica nanoparticles and application of shear had little effect on the resultant crystal structure. [DOI 10.1295/polymj.36.519] KEY WORDS Poly(trimethylene terephthalate) (PTT) / Nanocomposites / Crystallization / Nucleation / A variety of inorganic materials, such as glass fiber, talc, calcium carbonate, and clay minerals, have been widely used as additives or reinforcements to improve the thermal and mechanical properties of organic polymers. The key factors to enhance such properties include the size, shape, dispersion state, and interfacial adhesion of fillers in the polymer matrix. In recent years, the organic nanocomposites incorporating some nano-sized inorganic particles have attracted much attention as newly emerging materials. When compared with the conventional composites including submicron inorganic particles the nanocomposites are expected to give new and much improved properties even at the same composition.1-3 Some examples include increase of tensile modulus and strength, barrier properties, resistance to solvent, fire and heat, and optical transparency. [4][5][6] Moreover, these improvements are expected to be obtained at much lower loading levels than the submicroparticles. The desired content of 1-10 wt % for nanoparticle is comparable with that of 25-40 wt % for submicronparticles in efficiency. Recently, poly(trimethylene terephthalte) (PTT) attracts much attention among polymer processors and is being intensively investigated as engineering thermoplastics and as a matrix for fiber-reinforced composite due to its good thermal and mechanical properties. 8,9 In addition, PTT is predicted to obtain a large share in synthetic fiber market in the future because of its peculiar properties. Fumed silica nanoparticles manufactured by high-temperature hydrolysis of silicon tetrachloride in a flame has a spherical shape, extremely large surface areas, and a non-porous surface, which could promote physical contact with polymer matrix.10 Sumita et al. 11 early pointed out the benefits of re...

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“…However, this kind of polymerization history can be eliminated easily by a thermal treatment of the PVC powders above Tg. 17 The influence of the Tg of rigid PVC on the crystallization process during the polymerization indicates that no significant swelling of PVC by its monomer occurs during the polymerization process, as suggested by B e r e n~. *~ Otherwise, this polymerization history effect would not have been observed because of the considerably lower glass-transition temperature during the polymerization in the case of plasticization of PVC by its monomer.…”

Section: Waxs Patterns Of the Conversion Seriesmentioning

confidence: 92%

Structural aspects of suspension poly(vinyl chloride): Influence of temperature on the macro‐ and microstructure

Scherrenberg

Reynaers

Gondard³

et al. 1994

J Polym Sci B Polym Phys

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The structural aspects of rigid suspension poly(vinyl chloride), PVC, have been investigated on the basis of two independent series of suspension PVC samples, polymerized at temperatures between 26 and 84°C. The reproducibility of the suspension polymerization process and the importance of the polymerization temperature with respect to the macro‐ and microstructure is demonstrated. Quantitative examination of the grain structure by small angle neutron scattering, Brunauer‐Emmett‐Teller absorption technique, and mercury porosimetry clarifies the gradual increase of the specific surface on lowering the polymerization temperature. A detailed WAXS study shows an increasing degree of crystallinity on lowering the polymerization temperature, which can be associated with the corresponding increase of the syndiotacticity. Furthermore, the presence of a polymerization history in the PVC powders with respect to the crystallinity is evidenced. This effect seems to be related to chain mobility restrictions during the polymerization process and is determined by the difference between the polymerization temperature and the glass‐transition temperature (Tg) of rigid PVC. This so‐called Tg effect is indicative of the fact that no appreciable swelling of PVC by its monomer occurs. © 1994 John Wiley & Sons, Inc.

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Structural aspects of suspension poly(vinyl chloride): The thermal aspects of rigid suspension PVC

Cited by 12 publications

References 26 publications

U‐PVC gelation level assessment, part 1: Comparison of different techniques

U‐PVC gelation level assessment, part 1: Comparison of different techniques

Effect of Silica Nanoparticle on the Quiescent and the Shear Induced Crystallization Behaviors of Poly(trimethylene terephthalate)

Structural aspects of suspension poly(vinyl chloride): Influence of temperature on the macro‐ and microstructure

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