Plasticizers alcohol structure effects

Table 24.4 Generalized Effects of Alcohol Structure on Performance of Plasticizers [25]...

Effect of Plasticizer Shape. Extended plasticizer molecules such as aliphatic chains with a high degree of flexibility, usually lower Tg or Tc much more than bulky plasticizer molecules, such as those containing ring structures. However, Table XIII shows that the comparison between aliphatic and aromatic ester plasticizers is also determined by the length of the alcohol residues and by separation between the ester groups. 

Extrusion is a cost effective manufacturing process. Extrusion is popularly used in large scale production of food, plastics and composite materials. Most widely used thermoplastics are processed by extrusion method. Many biopolymers and their composite materials with petroleum-based polymers can also be extruded. These include pectin/starch/poly(vinyl alcohol) (Fishman et al. 2004), poly(lactic acid)/sugar beet pulp (Liu et al. 2005c), and starch/poly(hydroxyl ester ether) (Otey et al. 1980), etc. In this study, composite films of pectin, soybean flour protein and an edible synthetic hydrocolloid, poly(ethylene oxide), were extruded using a twin-screw extruder, palletized and then processed into films by compression molding process or blown film extrusion. The films were analyzed for mechanical and structural properties, as well as antimicrobial activity. 

Additives of this group are based on polymeric alcohols and polysaccharides adapted for the particular application. In addition to their effects as adhesives they can also, depending on their structure and molecular weight also exhibit thickening and hence plasticizing and lubricating properties. The contact mediation with the particular raw material to the ceramic particle surface and their effect as initiator of a lubricating film between the particles have already been described in the previous discussions. 

Terephthalate esters are not as compatible as phthalates with PVC and are more difficult to process. Today there is essentially only one important terephthalate plasticizer commercially available, DEHTP, as terephthalate esters of C9 and CIO alcohols have compatibility issues. The diisoheptyl terephthalate ester was shown [27] to have advantages in processabihty and plasticizing efficiency over DEHTP, but with hmited availability of isoheptanol, this product was never commercialized. The terephthalate ester based on C4 alcohols, dibutyl terephthalate (DBTP) is now commercially available for use in plasticizer blends to help improve processability [28] of DEHTP. Although DEHTP is very similar to the structure of DEHP, the structural difference yields important effects in the plasticizer toxicity profile. Extensive testing of DEHTP confirms that it is a safer product than DEHP [24]. 

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