METHOD FOR RAPID EVALUATION OF SAFETY OF ARTICLES MADE OF PHENOL-FORMALDEHYDE PLASTIC

摘要

FIELD: chemistry.SUBSTANCE: safety of articles made of phenol-formaldehyde plastic is evaluated using a multichannel gas analyser (MAG-8) with 8 piezo-quartz resonators, the electrodes of which are modified by applying solutions of polydiethylene glycol succinate, polyethylene glycol sebacate, polyethylene glycol phthalate, polyphenyl ether, trioctylphosphine oxide, bee glue, beeswax and a composite sorbent - bee glue with iron (III) chloride. The mass of the sorbent film is 15-20 mcg after removing the solvent at 40-50°C for 15-20 min. The modified piezo-quartz resonators are then placed in the closed detection cell of the MAG-8 and held for 5 min to establish a stable zero signal. Further, 5.00 g of a ground sample of phenol-formaldehyde plastic is placed in a sampler which is then tightly closed with a polyurethane plug and held at 20±1°C for 15 min to saturate the gas phase with phenol vapour. Further, 3 cmof the equilibrium gas phase is collected through the polyurethane plug and injected into the closed cell of the MAG-8, followed by measuring the change in the oscillation frequency of the piezo-sensors for 120 s and calculating the area of the "visual print" S, Hz·s, using the formula S=f(C), S=1959·C+35. For the calculation, a calibration curve of S, Hz·s versus phenol concentration C, mg/dmis plotted first. If the area S?130±10 Hz·s, the concentration of free phenol in the equilibrium gas phase over the phenol-formaldehyde plastic C0.05 mg/dmexceeds the recommended level for food plastics, and if S260 Hz·s or higher, high content of phenol and formaldehyde is recorded.EFFECT: invention provides fast evaluation of safety of articles made of phenol-formaldehyde plastic.2 dwg, 1 ex