PVC/PEO blends

The miscibility of PVC with PEO, in PVC/PEO blends was investigated by viscometric, microscopic, and thermal analyses. Viscometric and thermal results showed that the PVC/PEO blends were miscible. Polymer polymer interaction parameters, determined by depression of the melting temperature are negative and showed to be dependent on the molecular weight of PVC. The miscibility of the PVC/PEO blend was explained as a result of donor-acceptor interactions between chlorine atoms of PVC, as a weak acceptor species, and oxygen atoms of the PEO as a donor species (Neiro et al., 2000). 

The blending of PVC with PEO results in the formulation of a semicrystalline PVC/PEO matrix with improved properties that are complementary with the characteristics of each of the homopolymers. Some of the properties possessed by PVC and PEO that have set barriers for their individual use in the preparation of polymer electrolytes, have been identified as being suppressed in the PVC/PEO blend. This makes the matrix well-suited to applications in electronic devices, owing to its improved electrical, mechanical, and thermal characteristics. 

The properties possessed by the PVC/PEO blend alone are insufficient to support its application in electronic devices, especially in terms of thermal resistance. Consequently, several different types of additive can be incorporated into the polymer blend for the purpose of formulating a matrix with a better thermal profile. 

In System 2, the thermal properties of the PVC/PEO blend are tailored by the addition of LiCEsSOs, which is dissolved separately in THE prior to its addition to... 

The TGA curve of a PVC/PEO blend is shown in Figure 11.5. This blend was seen to experience a total weight loss of 51.5 wt%, and to have an improved thermal stability compared to pure PVC. These data help to explain the choice of polymer blending technique used when developing high-thermal resistance matrices containing PVC polymers. The thermal properties of the PVC-based formulations were also shown to be improved when blended with poly(isobornyl acrylate) (PIBA), as reported by Kok et ol. [22]. 

The second decomposition temperature of the blend is approximately 245 °C this value was seen to be lower than that obtained in pure PVC and pure PEO. The reduction in the second decomposition temperature was attributed to the presence of a high amorphous phase concentration in the PVC/PEO matrix. The atoms present in the PVC/PEO blend are diffused far into the amorphous phase and are bonded together by weaker interactions consequently, only a small amount of heat would be sufficient to disrupt or break these loosely held atoms. This is suggested as being the reason for the observed reduction in second decomposition temperature of the blend when compared to neat PVC and PEO. 

Mauro da Silva Neiro, S., Cardosa Dragunski, D., Forti Rubira, A., and Curti Muniz, E. (2000) Miscibility of PVC/PEO blends by viscometric, microscopic... 

More recent research investigates possibility of obtaining blends of PVC with conductive polymers. Figure 3.33 shows that concentration of conductive polymer is essential for conductivity. Optimal conductivity is obtained at a certain range of PVC concentration. The blends of poly(ethylene oxide), PEO, poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate), PEDOT-PSS, and PVC were designed to maximize thermal stability and conductivity. The thermal stability of the blend is increased by PEO and conductivity is increased by increasing concentration of PEDOT-ESS." Conductivity of PVC-NBR blends can be increased by addition of polyaniline-DL-camphor sulfonic acid, PANI-CSA. The conductivity of the blend increases linearly with the amount of PANI-CSA." ... 

In System 4, efforts were made to improve the thermal profile of the PVC/PEO-LiCF3S03-DBP EC blend by incorporating Si02 particles into the matrix. In this case the heat-stabilized Si02 particles were suspended directly into the blend solution, which was stirred overnight at room temperature to achieve a homogeneous, viscous mixture. When the suspension was poured into a Petri dish and allowed to evaporate slowly inside a desiccator, the final product was a mechanically stable, free-standing thin film. 

RAMESH, s., YAHAYA, A.H., AROF, A.K., Miscibility studics of PVC blends (PVC/ PMMA and PVC/PEO) based polymer electrolytes. Solid State Ionics, 2002, 148,483-6. 

Figure 3.33. Electric conductivity of ternary blend (PEO/PVC/PEDOT-PSS) vs. content of PVC in the blend. [Adapted, by permission, from Rinaldi, A. W. Matos, R. Rubira, A. R Ferreira, O. R Girotto, E. M., J. Appl. Pofym. Sci.,96, 5,1710-1715,2005.]...

Density and solubility parameter as a function of chain length for (a) polyethylene oxide (PEO) and (b) polyvinyl chloride (PVC). (From Luo, Z. L., and Jiang, J. W. 2010. Molecular dynamics and dissipative particle dynamics simulations for the miscibility of poly(ethylene oxide)/ poly(vinyl chloride) blends. Polymer 51 291-299.)... 

The miscibility of PEO/PVC blends has been investigated by Luo and Jiang by MD simulations. It was found that 40 repeated units are sufficient to represent a PEO chain and 50 for a PVC chain. Based on the temperature dependence of... 

Electrical conductivity measurements have been reported on a wide range of polymers including carbon nanofibre reinforced HOPE [52], carbon black filled LDPE-ethylene methyl acrylate composites [28], carbon black filled HDPE [53], carbon black reinforced PP [27], talc filled PP [54], copper particle modified epoxy resins [55], epoxy and epoxy-haematite nanorod composites [56], polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) blends [57], polyacrylonitrile based carbon fibre/PC composites [58], PC/MnCli composite films [59], titanocene polyester derivatives of terephthalic acid [60], lithium trifluoromethane sulfonamide doped PS-block-polyethylene oxide (PEO) copolymers [61], boron containing PVA derived ceramic organic semiconductors [62], sodium lanthanum tetrafluoride complexed with PEO [63], PC, acrylonitrile butadiene [64], blends of polyethylene dioxythiophene/ polystyrene sulfonate, PVC and PEO [65], EVA copolymer/carbon fibre conductive composites [66], carbon nanofibre modified thermotropic liquid crystalline polymers [67], PPY [68], PPY/PP/montmorillonite composites [69], carbon fibre reinforced PDMS-PPY composites [29], PANI [70], epoxy resin/PANI dodecylbenzene sulfonic acid blends [71], PANI/PA 6,6 composites [72], carbon fibre EVA composites [66], HDPE carbon fibre nanocomposites [52] and PPS [73]. 

Polymer electrolytes are used in lithium ion rechargeable batteries. Pure polymer electrolyte systems include polyethylene oxide (PEO), polymethylene-polyethylene oxide (MPEG), or polyphosphazenes. Chlorinated PVC blended with a terpoly-mer comprising vinylidene chloride/acrylonitrile/methyl methacrylate can make a good polymer electrolyte. Rechargeable lithium ion cells use solid polymer electrolytes. Plasticized polymer electrolytes are safer than liquid electrolytes because of a reduced amount of volatiles and flammables. The polymer membrane can condnct lithinm ions. The polymer membrane acts as both the separator and electrolyte [7],... 

Copolymerization with other vinyl monomers, such as St and VAc, allows for further modification of acrylic and methacrylic esters. The ease of structural modification to produce desired blend properties (miscibility) is well-documented in the experimental literature. The common methacrylate polymer is PMMA and has been noted to be miscible with various other polymers such as PVC and PEO. 

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