Dynamic‐mechanical study of the secondary transition of poly(vinyl chloride)

Pezzin, G.; Ajroldi, Giuseppe; Garbuglio, C.

doi:10.1002/app.1967.070111215

Cited by 96 publications

(15 citation statements)

References 21 publications

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“…At the same time the stiffness increases and the impact strength decreases [2]. This phenomenon is known as "antiplasticization" and has been attributed either to an increasing crystallinity [3][4][5] or to a decrease of the 'free volume' [6,7], as well to PVC-plasticizer interactions [8][9][10]. According to the last two assumptions the plasticizer hinders local or cooperative motions of shorter segments of the PVC chain.…”

Section: Introductionmentioning

confidence: 98%

A DMA study of the suppression of the Β transition in slightly plasticized PVC blends

Vilics

Schneider

Manoviciu

et al. 1996

Journal of Thermal Analysis

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A new criterion for evaluating different plasticizers the ability of suppression of the 13 transition in plasticized PVC blends. Accordingly, the ~3 suppression ability is proportional to the PVCplasticizer compatibility, expressed either by the critical solution temperature, CST, or by the interaction parameter related to the difference between the solubility parameters of the blend components. The criterion is, however, valid for low plasticizer contents (<5% w/w) only, as long as the 13 transitions are not overlapped by the ct transitions, shifted towards lower temperatures due to the effect of the plasticizer. For higher plasticizer contents the a transition starts to overlap the 13 transition and the 13 suppression ability of the plasticizer depends increasingly on the efficiency of the plasticizer i.e. on the depression of the glass transition temperature of PVC (related to the Tg of the plasticizer). Accordingly, plastieizers with both good efficiency (low Tg) and compatibility are more effective in the 13 suppression than plasticizers which have only a higher compatibility but also a high Tg (i.e. reduced efficiency).

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Section: Introductionmentioning

confidence: 98%

A DMA study of the suppression of the Β transition in slightly plasticized PVC blends

Vilics

Schneider

Manoviciu

et al. 1996

Journal of Thermal Analysis

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“…This result differs somewhat from that achieved by Pezzin's measurements carried out on copolymer vinyl chloride-ethylene. 6 Polyethylene chlorinated to the same chlorine content as PVC (sample 6) is showing the characteristic &maximum. The lower T , as well as the enlargement of the left part of the &peak, however, give evidence of the presence of unchlorinated polyethylene sequences.…”

Section: Resultsmentioning

confidence: 94%

“…From the extensive study of Pezzin and co-workers, 6 it becomes evident that the shape, intensity, and position of the @-process is not affected by the free volume, the 20% of crystallinity, nor by local changes in the distribution of chlorine atoms, for instance, by head-to-head structure. The decrease in the @-maximum is caused by adding a small quantity of plasticizer whereby at the same time the @-peak is slightly shifted to lower temperq-t~r e s .~J A conspicuous change of shape and position of the &peak i s * brought about by the heterogeneous chlorination of poly(viny1 chloride) .6J'- 9 In this case, the secondary peak is broadened and shifted to higher temperatures.…”

Section: Introductionmentioning

confidence: 99%

The secondary relaxation process of poly(vinyl chloride) and its derivatives

Heidingsfeld

Zelinger

Kuška

1971

J of Applied Polymer Sci

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SynopsisThe temperature dependence of the shear modulus G' aud of the damping tan 6 of poly-(vinyl chloride), poly(viny1idene chloride), copolymers of vinyl chloride-vinylidene chloride, PVC chlorinated in solution and suspension, and chlorinated polyethylene was measured. Secondary relaxation process of PVC and its derivatives are being explained as vibration of methylene groups polarized by neighboring CC1 dipoles. This process, being suppressed by lowering the concentration of the methylene groups in the PVC chain (e.g., by chlorination), remains, however, unaffected by the growth of crystalline content. The achieved results show that in the a-transition region there occurs, in accordaece with Andrews' theory, a loosening of the bonds between the CCl dipoles, whereas in the &transition region a loosening of the weaker bonds among the dipoles of the polarized methylene .

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“…1,2 This phenomenon, called antiplasticization, has been observed in polymers such as polycarbonates, 3,4 aromatic backbone polymers, 5 epoxy resins, 6 PVC, 1,7 and others. A characterization of the sub-T g relaxations reveals that, together with the decrease of the glass transition temperature, the progressive disappearance of secondary sub-T g relaxations ( -relaxation) is also taking place.…”

Section: Introductionmentioning

confidence: 97%

Secondary Relaxations in PVC As Studied by Phosphorescence Decay of Grafted Luminescent Probes

et al. 2005

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Secondary relaxations have been detected in poly(vinyl chloride) (PVC) by measuring the phosphorescence emitted by chromophores present as defects in the polymer chains and in PVC with luminescent probes, pyridine and naphthalene, grafted onto the chain. The measurement of phosphorescence decay with temperature allows to identify the existence of two components in the -relaxation of PVC: one at about -40°C and the other at about -60°C. The progressive introduction of luminescent probes grafted on the PVC backbone and the study of such luminescent copolymers permits to attribute the well-known decrease of the -relaxation intensity when grafting or plasticizing, to the progressive disappearance of the high-temperature component. The spectral analysis of the mercaptopyridine grafted PVC copolymer (PVC-PYR) in the temperature range -130 to -30°C shows that contiguous modified segments which interact with one another do not relax, while isolated modified segments do relax, either because isolated modified segments display the motions characteristic of the relaxation or because they are sensible to the motions of contiguous unmodified PVC segments.

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Dynamic‐mechanical study of the secondary transition of poly(vinyl chloride)

Cited by 96 publications

References 21 publications

A DMA study of the suppression of the Β transition in slightly plasticized PVC blends

A DMA study of the suppression of the Β transition in slightly plasticized PVC blends

The secondary relaxation process of poly(vinyl chloride) and its derivatives

Secondary Relaxations in PVC As Studied by Phosphorescence Decay of Grafted Luminescent Probes

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