Thermally induced redistribution and degradation of bisphenol-A polycarbonate fractions in open and closed systems

Mathematical Modelling and Computer Simulation of Linear Polymer Degradation: Simple Scissions

“…The rise in volatile (monomer) products or lower oligomers with the rise in the thermal energy has been hypothesised due to significantly high occurrences in unzipping or invasion in HMW region. [32,33,39] The kinetic potential of cleavage at a particular bond site along the chain backbone can be elucidated from the determination of the product sizes during or at the end of decay. [57,69,71,83] …”

Detoxification of bisphenol A via sulfur-mediated carbon–carbon σ-bond scission

“…62 The compound O,O ′ -dimethyl bisphenol A (DMBPA) was selected as the substrate because it can be readily obtained from BPA-containing plastic wastes via lowtemperature (35-40 °C) C-C bond scission. 61 Thermal decomposition studies of BPA and its derivatives [49][50][51][52][53][54][55][56][57][58][59][60] have revealed that C aryl -C alkyl s-bond scission becomes signicant at 310 °C (Scheme 1C). We therefore combined DMBPA and elemental sulfur in a 1 : 9 mass ratio in a Parr bomb reactor under a nitrogen atmosphere, and then heated the mixture to 310-325 °C for 4 h. Upon cooling to room temperature, the product BC90 was isolated as a black, glassy solid that could be remelted readily (Scheme 2).…”

“…35 We therefore hypothesized that similar thermal decomposition of other anisole-containing compounds in the presence of elemental sulfur would likewise yield HSMs through the formation of C aryl -S bonds (Scheme 1C). [49][50][51][52][53][54][55][56][57][58][59][60] Thermal recycling of BPA-containing plastics yields the anisole-containing compound O,O ′ -dimethyl bisphenol A (DMBPA) via photo-induced catalytic C-C bond scission at only 35-40 °C. 61 Because DMBPA contains anisole subunits, we hypothesized that the reaction conditions developed by our group for the conversion of guaiacol to GS80 would likewise yield HSMs in which the DMBPA had been broken down into monoaryl species.…”

Activated carbonates: Enabling the synthesis of differentiated polymers via solution carbonation

“…In the melt polymerization of polycarbonate, trans-reactions lead to the randomization of the monomer residue units, limiting the possibility of producing segmented block copolymers at temperatures above 190 °C [24,29]; complete redistribution of the units was observed within 80 min for a polycarbonate with M n = 10 kg/mol [24].…”

“…Solution polymerization is a more desirable approach when using thermally sensitive monomers or in specific processes where low viscosity or dilute systems have a benefit (e.g., fiber impregnation or coating processes). In contrast to melt transcarbonation conditions [22,23], solution polymerization is expected to not suffer from transreactions and thus should enable the synthesis of multi block-(co) polycarbonates, provided that the temperature can be kept well below 190 °C [24]. Carbonate donors suitable for solution polymerization such as phosgene, di-and triphosgene, have sufficiently high reactivity, but also require a complex process design and strict safety measures (especially on a large scale), making BMSC an attractive alternative.…”