Plastics monomers

Calculation of paleopressure and thus the success of this approach to determining paleoelevation depend upon our ability to accurately measure the size distribution of vesicles in hand samples of basalt (Fig. 4). In the course of our research, we have developed three techniques for measurement. The first involved injecting hand samples with plastic monomer which subsequently polymerized, and then dissolving away the basalt to leave a large number of plastic casts of vesicles for measurement and counting. The plastic casts were resistant to the effects of HF acid, so they reliably represented the actual vesicle sizes and shapes but were difficult to measure accurately and very tedious to work with (Sahagian et al. 1989). This was a laborious and inefficient technique that should be abandoned in favor of faster and more accurate methods. 

Aliphatic and alicyclic amines form one of the most extensively used categories of compounds in a variety of manufacturing industries. These compounds are first-phase materials for chemical synthesis, intermediates, pharmaceuticals, pesticides, soil sterilizers, and several kinds of solvents, rubber products, rocket propellants, and plastic monomers. This chapter discusses the safety and toxicity of selected compounds handled by workers in different industries. More information and extensive literature are available in several study reports on members of this important group.31,32... 

Philo M R, Jickells S M, Damant A P and Castle L, 1994, Stability of plastics monomers in food-simulating liquids under European Union migration test conditions. J. Agric. Food. Chem. 42,1497-1501. 

Key Q powdered resin compositions R = a(jueous latexes, emulsions, dispersions S- organic lacquer solutions and dispersions T - plastisol and organosol formulations U = natural and synthetic rubber compositions V = hot-melt compositions W = thermoplastic masses X = oleoresinous compositions Y = reading formulations, eg.. epoxy and polyester Z = plastic monomers Dry thickness-... 

Nebulizer solutions are typically filled as unit dosages in plastic containers. The latter uses blow-fill-seal technology [33]. Thus drug formulation compatibility with plastics is an important factor. Characterization of any sorption processes of plasticizer, monomer, and extractables or leachables is critical during long-term product-evaluation studies. Such sterile unit-dose formulations, in essence, do not require chemical preservation. 

Most (97% to 98%) of the nitrobenzene produced is retained in closed systems for use in synthesizing aniline and other substituted nitrobenzenes and anilines (Dorigan and Hushon 1976 Chemical Marketing Reporter 1987). Most of these products go into the manufacture of various plastic monomers and polymers (50%) and rubber chemicals (27%) a smaller proportion goes into synthesis of hydroquinones (5%), dyes and intermediates (6%), drugs (3%), and pesticides and... 

VOCs as aromatic hydrocarbons and plastic monomer residues emitted from copied, laser-printed and matrix printed paper have been measured by the FLEC (Wolkoff et al., 1993b). Several of these compounds have also been identified in the corresponding tone powders. From a freshly photocopied paper, the initial SER of, e.g., styrene was 5 pg/ (m h). When handling 200 such copies in an office, the styrene concentration in the room air could be calculated to reach 12 pg/m. ... 

Polymer plasticization can be achieved either through internal or external incorporation of the plasticizer into the polymer. Internal plasticization involves copolymerization of the monomers of the desired polymer and that of the plasticizer so that the plasticizer is an integral part of the polymer chain. In this case, the plasticizer is usually a polymer with a low Tg. The most widely used internal plasticizer monomers are vinyl acetate and vinylidene chloride. External plasticizers are those incorporated into the resin as an external additive. Typical low-molecular-weight external plasticizers for PVC are esters formed from the reaction of acids or acid anhydrides with alcohols. The acids include ortho- and iso-or terephthalic, benzoic, and trimellitic acids, which are cyclic or adipic, azeleic, sebacic, and phosphoric acids, which are linear. The alcohol may be monohydric such as 2-ethylhexanol, butanol, or isononyl alcohol or polyhydric such as ethylene or propylene glycol. The structures of some plasticizers of PVC are shown in Table 9.1. 

Mitsubishi Int l./Plastics Monomer-Polymer Dajac Labs Nylon Engineering Plastics Color Compding. http //www.piasticscoior.com] Shuman Plastics http //www.shuman-piastics.com... 

Make Molymod models of the plastic monomers. Place these on the corresponding plastic information sheets. 

Acrylic, methacrylic and itaconic acids also act as plasticizers, so it should not be necessary to add any additional plasticizer comonomer such as MA. However, for textile tow precursor, it may be necessary to introduce either more of the acid comonomer, or add some plasticizer monomer to facilitate the introduction of crimp, which aids packaging of the textile tow. 

In acrylic latices, the hard monomer is methyl methacrylate and the plasticizing monomer an acrylate, such as butyl acrylate or one of the acrylate comonomers mentioned above. Acrylic latices usually contain copolymers of acrylic or methacrylic acid as colloids and thickeners, these being solubilized by neutralization with base. Whatever the type of latex, coalescing solvents are also normally added to improve film formation. These may or may not be water miscible and include alcohols, glycols, ether-alcohols, ether-alcohol esters and even hydrocarbons, all of high boiled point. 

Many contact sensitizers also have irritant properties. Patch testing with such sensitizers at high concentrations can cause an irritant reaction or a chemical burn, which seems to facilitate active sensitization. However, only a few sensitizers can cause chemical burns without occlusion, e.g., formaldehyde, chromic acid, amines, chloroacetophenone, some plastic monomers, and methylisothiazolinones. Even one single contact with these chemicals can both cause a chemical burn and induce sensitization, with a subsequent possible development of an allergic contact dermatitis (Bruze et al. 1990 Kanerva 1994). Therefore, when a potential sensitizer has caused a chemical burn, the patient should be patch tested with the sensitizer after healing of the burn, independent of any subsequent development of an eczema. 

Simultaneous patch-test reactions to p-tert-hutyl-phenol-formaldehyde resin and p-ferf-butylcatechol have been reported (Estlander et al. 1998), and p-tert-butylcatechol has been shown to be a component in at least some resins based on p-ferf-butylphenol-formal-dehyde (Zimerson and Bruze 1998). This can indicate a connection to other sources of p-ferf-butylcatechol, which is used as an antioxidant (Gellin et al. 1970) and as a stabiliser in different plastic monomers (Macfar-lane et al. 1990). 

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