Plastics. Also Britain

The October 1996 issue of the Dutch magazine Natuur Techniek makes mention of a research of the University of Bristol, Great Britain into the effects of implanting artificial hip joints and knees into the body. This research showed that metal particles and pieces of plastic, cement and polymers are gradually released from the artificial joints. Such particles were found in the neighbourhood of joints and lymph nodes. However, they were also present in the bone marrow, the spleen and the liver. The more artificial limbs are exposed to loads, the more particles will be released. So far there are no indications of health hazards, but it is not possible to predict long term effects. 

Chemically modified cellulose in the form of cellulose nitrate or nitrocellulose was made and tested for commercial applications in Britain in the 1855-1860 period without much success. The discovery by Hyatt, in 1863, that cellulose nitrate could be plasticized with camphor to give moldability to the blend, made this material much more useful. By 1870, celluloid (plasticized cellulose nitrate) was being produced into a variety of commercial products such as billiard balls, decorative boxes, and combs. Nitrocellulose was also soluble in organic solvents, unlike cellulose, and so could be applied to surfaces in solution to form a coating, as in airplane dopes and automobile lacquers. It could also be solution spun into fibers (synthetic silk) and formed into photographic film, or used as a laminating layer in early auto safety glass. It was also used as an explosive. The hazard introduced to many of these uses of nitrocellulose by its extremely flammable nature resulted in an interest to discover other cellulose derivatives that could still be easily formed, like nitrocellulose, but without its extreme fire hazard. 

Abundant byproducts of the Coalite process were also low temperature tars, containing cresylic acids (cresols the products were referred to as meta cresol and cresylic acid). With the sudden increase in the price of phenol around 1937, and further rises in 1938, both as a result of demand from the plastics industry (despite a general downturn in trade), it was suggested that Low Temperature Carbonisation Ltd. investigate catalysts suited to condensations of cresylic acids (as an alternative to phenol) with formaldehyde. Certainly there was a greater dependence in Britain on cresylics than was the case in the United States, because of their availability from coal-based processes. In the meantime Monsanto, which manufactured coal tar cresols (as did Yorkshire Tar Distillers), was considering the erection of a second British synthetic phenol plant. 

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