Miscibility in Blends of Poly(vinyl chloride) and Polylactones

Abstract

The miscibility of blends of poly(viny1 chloride) (PVC) with polylactones of the @-propiolactone series (poly(a-methyl-a-n-propyl-@-propiolactone) (MPPL), poly(a,a-dimethyl-P-propiolactone) or polypivalolactone (PPL), and poly(a-methyl-a-ethyl-@-propiolactone) (MEPL)) has been studied by measurements of specific heat, mechanical relaxation, and density. These measurements indicate that there is extensive mixing between the segments of the two components of each blend since a single glass transition temperature and a decrease in melting point have been observed. From the depression in the melting point data, the interaction parameter xlz has been shown to be equal to -0.29 and -0.05 for PVC/MPPL and PVC/PPL blends, respectively.Even if it is well known that poly(ecapro1actone) (PCL) is miscible with a large number of polymers,' it is not clearly understood why this is so. However, it has often been suggested that specific interactions can be the driving force toward the formation of blends. For example, Olabisi2 has concluded that the PCL/poly(vinyl chloride) (PVC) blends are a result of the proton donating character of the a-hydrogens of PVC combined with the proton accepting character of the carbonyl groups of PCL. On the basis of this conclusion, one can rationalize why PCL is generally miscible with polymers containing hydrogens with a proton donating character, or hydroxyl groups, as for example poly(hydroxy ether), poly(epichlorohydrin), and poly (3,3-bis(chloromethyl)oxacyclobutane) (penton). Similar specific interactions have been suggested in blends of poly(buty1ene terephthalate)/poly(hydroxy ether of Bisphenol A) (31, Nylon G/ethyleneacrylic acid ~opolymer,~ poly(viny1 chloride)/ethylene-vinyl acetate-SOz terp o l y m e r~,~ poly(hydroxy ether of Bisphenol A)/poly(cyclohexylenedimethylene tere/i~ophthalate),~ poly(caprolactone)/poly(hydroxy ether of Bisphenol A),3 poly(viny1 chloride)/poly(butylene terephthalate),'j poly(styrene)/ poly(pheny1ene oxide) ,7 poly(viny1idene fluoride) /poly-(methyl acrylate),8 poly(viny1idene fluoride)/poly(ethyl acrylate),8 poly(viny1idene fluoride)/poly(vinyl a~e t a t e ) ,~ poly(viny1idene fluoride)/poly(methyl methacrylate),1° poly(viny1idene fluoride) /poly(ethyl methacrylate),'O and poly(methy1 methacrylate)/styrene-acrylonitrile copo1ymers.l'Following Olabisi's proposal, blends of PVC with common polyesters are expected to be thermodynamically miscible. In order to check this hypothesis, we have chosen polyesters derived from 6-propiolactone substituted in a,a. This series of polymers presents a wide range of physical properties including degrees of crystallinity ranging from 10 to 80% and melting points ranging from 25 to 240It is then the purpose of the present paper to study the degree of miscibility of PVC/polylactone blends by measurements of glass transition temperature ( T J , melting point ( T J , density, and mechanical relaxation. These blends will be shown to be thermodynamically miscible at all compositions in agreement with Olabisi's proposal. These res...

Complicated phase behavior and ionic conductivities of PVP-co-PMMA-based polymer electrolytes

“…Several empirical and semi-empirical equations have been suggested for predicting the dependence of T g on the copolymer composition. In this study, we believed that the most suitable equation for a weakly interacting system would be the GordoneTaylor equation [19,20]:…”

Thermal transitions and polymer/polymer miscibility

“…Also, composition oscilla-tions with different Tg are present and suggest that the system does not possess complete miscibility at the molecular level. The enlargement has been well documented for polyester/nitrocellulose [17] and PVC/polyester [26] blends.…”

“…These features have been discussed by many authors for polymerplasticizers [8,[20][21][22] and polymer blends [7,8,12,15,17,[23][24][25][26], and correlated to the strength of the interaction [12,13,17].…”

“…The increase in ATg at the intermediate compositions reveals higher microheterogeneity than for the extreme compositions. The interaction parameter, ~12, obtained from calorimetric measurements, was calculated from Eqs (6) to (8) and the Tg vs. composition experimental data, which were used with conditions and restrictions to the values of the unknown variables, and with the assumptions that A is a composition quadratic function and that K is a linear function expressed as K= A' + Ew 2 (26) In this way, a minimization numeric method (Newton-Raphson) was applied in order to obtain the interaction parameter, ~12. It must be borne in mind that, even without these restrictions, the obtained values are near the calculated values if it is assumed that both K and A are functions of the composition.…”

Comparison of Miscibility and Morphology in Two Ternary Blend Systems: Effects of Binary Interactions

“…The generally observed decline in the melting temperature with increasing contents of the amorphous diluent leads to conclusion that B 12 and ÁH mix are negative for miscible binary blends. [40][41][42] Equation 5 suggests that the parameter, B, can be evaluated in exactly the same way for a ternary mixture as for a binary blend by determining the slope of the T m versus the amorphous volume fraction construction. Evaluation of B at PS/PCHMA (or PS/PPO) ratio of 1, should then allow evaluation of unknown interaction parameter for PS/PCHMA (or PS/PPO), B 13 (or B 0 13 ), via eqs 3 and 6.…”