Polymer additives environmental impact

The environmental effects of substituting bio-based polymers for petrochemical polymers on a large scale were estimated [13]. Two perspectives were taken. First, the savings of fossil fuels, the effects of greenhouse emissions and the consequences for land use (in Europe) were studied. Second, it was analysed whether the lower specific impact of bio-based potymers (e.g. kg-C02 eq. per kg of polymer) can (over)compensate the additional environmental impacts caused by expected high growth in petrochemical plastics. 

Environmental Impact of Ambient Ozone. Ozone can be toxic to plants, animals, and fish. The lethal dose, LD q, for albino mice is 3.8 ppmv for a 4-h exposure (156) the 96-h LC q for striped bass, channel catfish, and rainbow trout is 80, 30, and 9.3 ppb, respectively. Small, natural, and anthropogenic atmospheric ozone concentrations can increase the weathering and aging of materials such as plastics, paint, textiles, and mbber. For example, mbber is degraded by reaction of ozone with carbon—carbon double bonds of the mbber polymer, requiring the addition of aromatic amines as ozone scavengers (see Antioxidants Antiozonants). An ozone decomposing polymer (noXon) has been developed that destroys ozone in air or water (157). 

In polymer applications derivatives of oils and fats, such as epoxides, polyols and dimerizations products based on unsaturated fatty acids, are used as plastic additives or components for composites or polymers like polyamides and polyurethanes. In the lubricant sector oleochemically-based fatty acid esters have proved to be powerful alternatives to conventional mineral oil products. For home and personal care applications a wide range of products, such as surfactants, emulsifiers, emollients and waxes, based on vegetable oil derivatives has provided extraordinary performance benefits to the end-customer. Selected products, such as the anionic surfactant fatty alcohol sulfate have been investigated thoroughly with regard to their environmental impact compared with petrochemical based products by life-cycle analysis. Other product examples include carbohydrate-based surfactants as well as oleochemical based emulsifiers, waxes and emollients. 

Principal structures of aminic stabilizers, their involvement in individual degradation processes of polymers, behaviour in mixtures with other polymer additives and an outline of environmental impacts due to the amines are included. The most relevant literature sources published by the first quarter of 1994 are reported. Some earlier data has to be mentioned as a reminder of the original ideas and to improve the interpretation of results. Where relevant, recent comprehensive reviews are cited. Principal types of commercial stabilizers are included in Appendix. 

It should be noted, however, that the thermal and mechanical properties of vegetable fiber reinforced polymer composites are notoriously lower than those of similar composites reinforced with synthetic fibers (e.g., carbon, glass, aramid) [1, 2,12]. The above-mentioned techniques, i.e., fiber drying and surface treatment or the addition of a compatibilizer, are mostly not enough to adjust the properties of vegetable fiber reinforced polymers to the desired level. Moreover, even though these treatments enhance adhesion, there is some controversy in the literature about their effect on the mechanical properties of the fiber itself and even when a more pronoxmced gain is noticed after treatment, the improvement for the composite is often within the scatter of the results. In addition, the cost and environmental impact of some of these treatments, especially of those more elaborated, often prevent their industrial scale applications. 

I his hook (liTfiils Iho ulilisfilion ol a wide range of plastics waste in terms of optimising the proc essing and disposal ol polymers, which plays an important role in the success ol the plastics industry. In addition, the environmental impact of the plastics industry is also disc nssc cl. 

The resulting polymer, which is unsaturated on its terminal positions, is mixed with an unsaturated monomer, usually styrene. These reactive groups can form a cross-linked network with or without the addition of a comonomer. In many industrial products, vinylester resins include 40-50 wt% styrene, while in dental applications a common comonomer is triethylene glycol dimethacrylate. For some applications, such as filament winding, the styrene content needs to be limited (not normally exceeding 35-40%), reducing at the same time the quantity of volatile organic compounds (VOC) and therefore the environmental impact of the resin. 

---