Loss of plasticizers

Chlorinated terphenyls % Cl = 40-60) Poly(styrene glycol) Tri(ethylene glycol) ester of hydrogenated abietic acid Bisphenyl A-polysulfone ethers, polycarbonates Bisphenol A-polysulfone ethers, polycarbonates Bisphenol A-polysulfone ethers, polycarbonates 

Plastics containing low-molecular-weight plasticizers may become hard and brittle after a while, and this is accompanied by a decrease in weight due to loss of plasticizer. This loss changes the physical properties and the quality of a plastic material with time and may be caused by 

Plasticizer volatility. In this case, the vapor pressure of the plasticizer and the diffusion rate of its molecules within the polymer matrix play an important role, since the plasticizer molecules evaporate from the surface of the material. The loss of plasticizers from some plasticized PVC samples is given in Table 1.5 [70]. 

Extraction of plasticizer by solvents, water, oils, etc., in contact with the plastic material. 

Plasticizer Lost of plasticizer after 20 days at 60°C (% by weight) After 3 days at 85°C (% by weight) 

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Fig. 2. Volatile loss of plasticizers from flexible PVC (BSS 35) where M represents Cg [...

Emissions During Processing. During the production of flexible PVC products plasticizers are exposed for up to several minutes to temperatures of - ISO C. The exact conditions depend on the processing technique employed, but it is evident that the loss of plasticizer by evaporation and degradation can be significant. 

It is desirable that the plasticizer compounded with a polymer be permanently retained. Loss of plasticizer changes the properties of a given formulation, and can be produced by volatilization, extraction or migration. The volatility of a plasticizer in a formulation can be related to the surface area, thickness of the polymeric material, and viscosity (e.g. molecular weight) of the plasticizer itself. 

ISO 176, Plastics - Determination of loss of plasticizers - Activated carbon method, 1976. 

After the failure criterion has been defined, the various processes that could cause this failure must be analyzed. For example, an increase in modulus could occur by thermal oxidation, increased postcure crosslinking, or the loss of plasticizer. Whatever the mechanism, each possible process needs to be identified and its rate characterized separately. Only then can interactions between different mechanisms be considered for life prediction. 

Organic insulating materials are generally subject to temperature dependent deterioration during their operational lifetime. The relevant chemical processes are complicated and may be described (with a certain simplification) as slow oxidation which introduces acid groups into the polymeric insulation, the loss of plasticizer, oxygen cross-linking of polymer chains and internally catalysed depolymerization of plastic insulation. 

Whitney, 1996 Webb et al., 1999, 2000) where degradation of the additives, particularly the plasticizers, causes an increase in brittleness, loss of plasticity and fragmentation (Roberts Davidson, 1986 Webb et al., 2000). 

In the present chapter, we have not discussed cell-cell interaction and have restricted our study only to a production process of a single cell. Of course, cells start to interact with each other, as the cell density is increased through the cell division. Indeed, including the cell-cell interaction to the present cell model with reaction network, cell differentiation and morphogenesis of a cell aggregate are studied [15,16]. Through instability of intracellular dynamics with cell-cell interaction, cell differentiation, irreversible loss of plasticity in cells, and robust pattern formation process appear as a general course of development with the increase of the cell number. Relevance of minority control and deviation from universal statistics to such multicellular developmental processes will be an important issue to be studied in the future. 

The sideeffect may be a hardening of the material from the loss of plasticizers or from the loss of other low molecular additives or even water, which can act as plasticizers. Differential expansion of organic and inorganic additives can result in cracking of the polymeric materials. 

The low-temperature oxidation of coal dramatically influences and alters inherent properties. The deleterious effect that oxidation has upon the coking and caking properties of coal, through the loss of plasticity and fluidity, is well known. 

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