Processing of poly(vinyl chloride) polymers correlated with composition, glass transition, and viscosity

ABSTRACT:The article presents an investigation into the use of plasticizers for reducing the degree of association existing within lignin molecules, in order to overcome adverse effects on the mechanical properties of its blends with a vinyl chloride-vinyl acetate (VC-VAc) copolymer. Infrared spectroscopy and differential scanning calorimetry were performed to examine the effect of the plasticizer type and concentration in plasticizing Alcell, an organosolv lignin. The results show that the compatibility and efficiency of a plasticizer are strongly influenced by the solubility parameter, which should be close to that of the lignin. Polyblends prepared with several plasticizers, Alcell lignin, and the VC-VAc copolymer were also investigated by thermal analysis and mechanical testing. Variations in the mechanical properties of these blends were found to correlate with the lignin dispersion quality and with the plasticizer efficiency in Alcell lignin.

Section: Resultsmentioning

confidence: 99%

Blends of vinylic copolymer with plasticized lignin: Thermal and mechanical properties

Feldman

Banu

Campanelli

et al. 2001

“…The decomposition of poly(viny1 chloride) (PVC) at elevated temperatures has been studied by a number of investigators using a variety of techniques including HC1 evolution, l-a infrared4s6 or mass ~pectroscopy,~J thermal gravimetric analysi~,~-~ oven aging, and the Brabender Plasticorder. [12][13][14][15][16] However, only the Brabender or the dynamic thermal stability (DTS) test, utilizes the rheological behavior of the bulk polymer as a criterion of degradation. With this instrument the amount of torque required to shear mix the polymer is measured and is proportional to the melt viscosity of the sample and, as such, should reflect the structural changes occurring in the polymer.…”

Section: Introductionmentioning

confidence: 99%

Poly(vinyl chloride) thermal stability. I. Evaluation by melt rheology

Collins

Krier

1966

SynopsisCapillary rheometry is used to characterize the thermal stability of poly(viny1 chloride). By isothermally extruding the polymer melt at constant shear rate, apparent viscosity-time relationships are obtained having three distinct regions: ( 1 ) obtainment of equilibrium viscosity, ( 2 ) constant viscosity, and (3) rapidly changing viscosity. During regions 2 and 3 the polymer extrudate gradually changes in color from water clear to black. These characteristic regions are related to the temperature of extrusion by Arrhenius plots. An activation energy of 40 kcal./g.-mole w&s calculated for the decomposition of PVC. Infrared spectroscopy, thermal gravimetric analysis, and intrinsic viscosity experiments are used to corroborate the results of the melt flow data.

“…It has been demonstrated that the forces involved in mixing a highly viscous melt can be correlated with the melt viscosity 15. From the data shown in Table III, we see that the type of plasticizer, as well as the level of AL, has a distinct influence on the mixing torque of the controls and blends.…”

Section: Resultsmentioning

confidence: 73%

Highly filled blends of a vinylic copolymer with plasticized lignin: Thermal and mechanical properties

Feldman

Banu

Manley

et al. 2003

ABSTRACT:The objective of this study was the development of new vinyl flooring formulations with increased resistance to attack by fungi and microorganisms, formulated with plasticizers having chemical compositions different from that of common dioctyl phthalate (DOP). Alkyl phthalate plasticizers are considered to be toxicological and ecotoxicological hazards, although this is still under debate. It is suspected that during the service life of poly(vinyl chloride) (PVC) flooring, the attack of fungi and microorganisms leads to the degradation of DOP and the release of some volatile organic compounds. For this reason, in the new flooring formulations, the vinyl chloride/vinyl acetate copolymer (VC-VAc) was partially replaced with lignin, a natural polymer and a major component of wood and vascular plants. Besides its other functions in wood, lignin imparts resistance to microorganisms. An organosolv lignin from Alcell Technologies, Inc. (AL), was used as a partial replacement of PVC. The influence of the new plasticizers, as well as the influence of the partial replacement of VC-VAc with lignin, on the morphology and thermal and mechanical properties of the composites was investigated with scanning electron microscopy, differential scanning calorimetry, and tensile testing. Butyl benzyl phthalate and diethylene glycol dibenzoate were used as plasticizers; both were compatible with PVC and AL. The results indicated that diethylene glycol dibenzoate was the best plasticizer for these blend composites. In these formulations, AL could replace up to 20 parts of the copolymer. At this level of replacement, the key mechanical properties of the new composites compared very favorably with those of the DOP control formulations. The obtained formulation will be tested further for resistance to fungi and microorganisms.