Technical grade poly

We have developed new reaction systems based on colloidal dispersions [23, 24], namely highly concentrated water-in-oil (gel) emulsions, which could overcome most of the disadvantages of the aqueoussolvent mixtures such as inactivation of the aldolase and incomplete aldehyde solubilization in the medium. These emulsions are characterized by volume fractions of dispersed phase higher than 0.73 [25] therefore, the droplets are deformed and/or polydisperse, separated by a thin film of continuous phase. Water-in-oil gel emulsions of water/Ci4E4/oil 90/4/6 wt%, where C14E4 is a technical grade poly(oxyethylene) tetradecyl ether surfactant, with an average of four moles of ethylene oxide per surfactant molecule and oil can be octane, decane, dodecane, tetradecane, hexadecane, or squalane, were typically chosen as reaction media [23, 26]. 

Technical-grade poly(eth5dene oxide) IBrom BASF, Ludwigshafen, Germany ... 

Purified terephthalic acid and dimethyl terephthalate are used as raw materials for the production of saturated polyesters. During 1993, the combined worldwide production of purified terephthafic acid plus dimethyl terephthalate exceeded 14 x 10 t (42), which is 80% of the total benzenepolycarboxyfic acid production. Terephthafic acid is also produced ia technical or cmde grades which are not pure enough for manufacture of poly(ethylene terephthalate). In almost all cases, the technical-grade material is immediately converted to purified terephthafic acid or dimethyl terephthalate, which together are the articles of commerce. 

The submitters used PHB=Poly-(R)-3-hydroxybutyric acid obtained from Marlborough Biopolymers Ltd., Rudby Hall, Hutton Rudby, Yarm, Cleveland, England, PHB homopolymer, BX G04, technical grade powder, MBL 100/703. The checkers used PHB from Fluka Chemie AG, CH-8470 Buchs, Switzerland. The submitters report that the procedure works well on batch sizes of 200-250 g. 

Oil-Based SINs. The SINs produced were based on a castor oil polyester-urethane and styrene crosslinked with 1 mole percent of technical grade (55%) divinyl benzene (DVB) (7). This structure may be written poly[(castor oil, sebacic acid, TDI)-SIN-(Styfene, DVB)], poly[(CO,SA,TDI)-SIN-(S,DVB)]. Benzoyl peroxide (BP) (0.48%) was used as the free radical initiator for the styrene and 1,4-tolylene-diisocyanate (TDI) was used as the crosslinker for the polyester prepolymer. A 500 ml resin kettle equipped with a N inlet, condenser, thermometer, and high torque stirrer was used as the polymerization reactor. 

In this work, MDI-terminated polyester prepolymer based on ethylene adipate polyol (Baytec MS-242) was used to prepare cast poly(ester urethane) materials. The HER-TG materials, HER-HP and HQEE were used as chain extenders. As discussed in section 8.4, technical grade HER materials contain various levels of high MW diols as reactive impurities. Therefore, as with poly(ether urethanes), the high MW diols are expected to play a major role in the performance of poly(ester urethanes) made with these materials. 

Polyfester urethanes) based on HER chain extenders behaved in the same way as poly(ether nrethanes). When the high MW diol content of the extender is increased, the storage modulus is decreased due to the reduction of the hard segment content. As was seen from thermal analysis, the thermal stability of the HER-HP extended elastomer is slightly higher than the technical grade materials. 

In 1991, the U.S. annual rate of production of formaldehyde was 7.0 billion lb [1]. Formaldehyde is usually available commercially as an aqueous solution. Aqueous solutions containing 30 wt% formaldehyde are stable at room temperature, but solutions containing hi er concentrations become cloudy on storage because of the formation of poly(oxymethylene)glycol [Eqs. (9) and (10)]. Technical-grade formaldehyde solutions contain a small amount of methanol, which suppresses the polymerization process. 

This is called a technical or cmde grade of terephthaUc acid, but the purity is typically greater than 99%. It is not, however, pure enough for the poly(ethylene terephthalate) made from it to reach the required degree of polymerization. The main impurity is 4-formylbenzoic acid [619-66-9] which is incompletely oxidized -xylene and is monofunctional with regard to esterification. 4-Formylbenzoic acid is usually referred to as 4-carboxybenzaldehyde (4-CBA) in the industry. 

A considerable proportion of technical methyl acetate is an 80 20 mixture of methyl acetate and methanol, which is mostly derived as a by-product from the production of poly(vinyl alcohol). The properties of this mixture, both chemical and toxicological, are dilferent from those of pure methyl acetate and the two grades should be treated as different products. 

Mowital types are poly(vinyl butyral) grades with different molecular weights and varying degrees of acetalization. Technical data sheets have been provided (19). 

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