Catalyzed Nucleation of Poly (Vinyl Chloride)

Abstract

Microscopically visible crystallization in a typical non-crystallizing organic polymer -poly(viny1 chloride) (PVC) is achieved by dissolving it in an appropriate solvent (cyclohexanonc) and inducing the nuclcation by introducing various insoluble crystallization cores -microcrystals of noble metals (Au, Pd, Pt, Rh, Ir, Ru, 0 s ) . It is established that the higher the melting temperature of the metal the higher its activity as a crystallization core in the heterogeneous nucleation of PVC.The reverse process-oriented crystallization of a foreign substance -NaCl crystals on PVC films is also demonstrated. This result gives an indication of precrystalline structures in seemingly amorphous PVC films.Die mikroskopisch sichtbare Kristallization eines orgdnischen Hochpolymers -Poly(vinylch1orid) (PVC), welches wegen seiner besondcrs stark ausgepragten Kristallizatjonstragheit bekannt ist, wird erreicht, indem das Polymer in einem gceignetem Losungsmittel (Cyclohexanon) gelost wird und die Kcimbildung durch die Einfuhrung von Kristallisationsinitiatoren-Mikrokristallen von Au und der Platinmetalle (Pd, Pt, Rh, Ir, Ru, 0s) erzwungen wird. Es erweist sich, daR die die Kristallisation katalysierende Wirkung von Au zu 0 s simbat mit wachscnder Schmelztemperatur der entsprcchenden Metalle anwachst. Der umgekehrte ProzeB des oricntierten Kristallisationsaufwachscns von NaCl auf dunnen PVC Filmen wird auch demonstriert. Dies weist auf cine vorkristalline Ordnung in den amorphen Filmen hin.

Effect of isothermal annealing on degree of crystallinity and mechanical properties of poly(l‐lactide‐co‐glycolide)

“…Figure 2 shows the polarization optical photomicrographs of the spherulites of PLLGA85/15 crystallized isothermally at different Tc's. As seen in figure 2, relatively normal spherulites were formed at 120 °C and 130 °C compared with the spherulites formed at higher Tc's, which were disordered or unstable [13]. Only www.crt-journal.org © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim small spherulite crystallites were formed when the Tc was lower than 120 °C.…”

PVC Morphology

“…According to Summers et al 84 PVC having K-value close to 50 has the average radius of gyration close to 10 nm. 87 This result of research should be treated as a specific case because research material was obtained under specific conditions of catalyzed nucleation on special crystallization cores. 85 There is still another explanation of the connectivity between crystallites by the fiberlike model which describes the molecular structure of PVC aggregates.…”

PVC Additives

“…114 The ethylene is there for strength, the acrylate or acetate for flexibility, and the carbon monoxide for polarity, thus making the polymers miscible with PVC. 114 The ethylene is there for strength, the acrylate or acetate for flexibility, and the carbon monoxide for polarity, thus making the polymers miscible with PVC.…”

“…114 The ethylene is there for strength, the acrylate or acetate for flexibility, and the carbon monoxide for polarity, thus making the polymers miscible with PVC. 114 Flexibilizers provide PVC with excellent flexibility and impact strength at low temperatures. 114 Flexibilizers provide PVC with excellent flexibility and impact strength at low temperatures.…”

“…114 ECR 741 and 742 are ethylene-vinyl acetate-carbon monoxide copolymers, and ECR HP 441 is a lower melt index copolymer of ethylene, acrylate, and carbon monoxide. 114 Table 3.26 contains information on PVC nucleating agents Polymer nucleation increases crystallinity and many mechanical properties of polymers. They are miscible with other plasticizers and PVC, permanent (they do not migrate), increase chemical and oil resistance of product, increase melt strength, and permit use of higher filler loading.…”