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Bisphenol A is difunctional and used to produce epoxy resin and polycarbonate. 4-tert-Butylphenol is monofunctional and so in polymer science terms, bisphenol A is a polymer chain extender but 4-tert-butylphenol is a chain stopper or sometimes called endcapper. It is thus use to control molecular weight by limiting chain growth.
3-dimensional [18 F]FDG-PET image with 3D ROI generated by a threshold based algorithm.The blue dot in the MIP image bottom right marks the maximum SUV within the ROI.. The standardized uptake value (SUV) is a nuclear medicine term, used in positron emission tomography (PET) as well as in modern calibrated single photon emission tomography (SPECT) imaging for a semiquantitative analysis. [1]
As each phenol group contains only a single t-butyl group they are considered to have low steric hindrance and thus high activity. Arranging three of these around an isocyanurate core gives a compound with a sufficiently high boiling point that it is not volatilised out of the plastic during plastic extrusion and moulding (up to 320 °C in the case of PA).
Fuel additives in the United States are regulated under section 211 of the Clean Air Act (as amended in January 1995). The Environmental Protection Agency (EPA) requires the registration of all fuel additives which are commercially distributed for use in highway motor vehicles in the United States, [8] and may require testing and ban harmful additives.
The chemical synthesis of BHT in industry has involved the reaction of p-cresol (4-methylphenol) with isobutylene (2-methylpropene), catalyzed by sulfuric acid: [11] CH 3 (C 6 H 4)OH + 2 CH 2 =C(CH 3) 2 → ((CH 3) 3 C) 2 CH 3 C 6 H 2 OH. Alternatively, BHT has been prepared from 2,6-di-tert-butylphenol by hydroxymethylation or aminomethylation ...
The term 'inhibitor' is often used in a general sense to describe any compound used to prevent unwanted polymerisation, however these compounds are often divided into 'retarders' and 'true inhibitors'. A true inhibitor has a well defined induction period during which no noticeable polymerisation takes place. They are consumed during this period ...
Polyisobutylene, also known as "PIB" or polyisobutene, (C 4 H 8) n, is the homopolymer of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based. Butyl rubber is produced by polymerization of about 98% of isobutylene with about 2% of isoprene.
Acute toxicity describes the adverse effects of a substance that result either from a single exposure [1] or from multiple exposures in a short period of time (usually less than 24 hours). [ 2 ] To be described as acute toxicity, the adverse effects should occur within 14 days of the administration of the substance.