Photodegradation of polystyrene containing flame retardants: Effect of chemical structure of the additives on the efficiency of degradation

Abstract

ABSTRACT:The efficiency and wavelength sensitivity of photodegradation in polystyrene (PSt) in the presence of a flame retardant were studied. The effect of the concentration of a flame retardant on the degradation of PSt was also investigated. Four kinds of flame retardant containing bromine atoms in the molecule and having the same frame structure were used. Irradiation of monochromatic radiation was carried out using the Okazaki Large Spectrograph (OLS). The degradation of the PSt matrix was followed by UV-visible and FTIR spectroscopy for the chemical changes produced. Changes in the molecular weight and its distribution were estimated from the results of a gel permeation chromatography (GPC) measurement. In all additives tested, the photodegradation of PSt was accelerated by the addition of bromine-containing flame retardants. The most effective wavelength for the main-chain scission of PSt was 280 nm for the samples containing 1 phr of the flame retardant, while this wavelength shifts to 300 nm for the samples containing 2 phr of the flame retardant. A probable reaction scheme of the accelerated degradation in the presence of a flame retardant was proposed from the experimental results. The photostability of PSt containing a flame retardant appears to depend on chemical structures of the additive and compatibility of the additives to PSt. Further studies are required to solve the role of additives in polymer matrices.

Flame retardant and toughening mechanisms of core–shell microspheres

“…The detailed data are summarized in Table 1. With addition of 15% CSP PS-APP , the T initial and T max1 of EP decreased to 332 o C and 349 o C respectively, and the char yield at 650 o C increased to 29.6%. The incorporation of CSP PS-APP into EP facilitates the decomposition of EP in 300-450 o C, while it makes the residue weight ratio at 650 o C increase up to above 15.0%.…”

“…The decomposition of EP initiates when it is heated to a certain onset temperature with some flammable gases generated in the reaction with oxygen. In these cases, hydrogen atom abstraction from α-position of PS produces a chain radical on the polymer [29] , which consequently induces a flaming combustion. In terms of the EP/CSP PS-APP composites, the CSP PS-APP will migrate to the surface of composites and aggregate with the aid of heat and gas flow in the soften EP matrix when the composites are exposed to fire or flame (Scheme 1 a).…”

Effect of Additives on Weathering

“…168 Extensive work was conducted to investigate the interference of flame retardants with stabilizers. 173,174,176 After acid exposure of polyolefins containing HALS, a dramatic loss of stabilizing efficiency has been observed.…”

“…Several other flame retardants did not perform well in the test because they did absorb energy from the daylight. 168,169 Light-stable retardant systems are available for polyolefins. 177 These flame retardants are combined with HALS which offers additional UV protection.…”

Data on Specific Polymers

“…Generation of large stresses during injection molding by ejecting parts prematurely and quenching them in a cold medium improved their mechanical properties and their resistance to ultraviolet radiation. 799 Flame retardants containing halogens increase the degradation rate of polystyrene by abstraction of hydrogen and formation of the polystyryl macroradical: 805 This increases the initiation rate. Further mechanism is similar to the described above.…”