Calix[4]pyrogallolarenes as novel high temperature inhibitors of oxidative degradation of polymers

Abstract

Oxidative stability of high density polyethylene containing C-alkylcalix[4]pyrogallolarenes was studied by Differential Scanning Calorimetry. The kinetic parameters of non-isothermal oxidation indicate that pyrogallolarenes are effective antioxidants at temperatures above 150 °C.

Fullerene C60 conjugated with phenols as new hybrid antioxidants to improve the oxidative stability of polymers at elevated temperatures

“…Rate constants (k, in min À1 ) for oxidation were calculated from the Arrhenius equation k ¼ Z exp(ÀE a /RT) for temperatures 50-250 C. Table 1 presents the overall Arrhenius kinetic parameters of oxidation of HDPE with and without additives. The activation parameters E a ¼ 129 AE 7 kJ mol À1 and Z ¼ 1.11 Â 10 14 min À1 obtained for non-inhibited process (no additives) are in good agreement with 127 AE 6 kJ mol À1 and 7.15 Â 10 13 min À1 measured earlier 24 as well as with other literature values. 10,29 The values of activation energy of HDPE oxidation vary with the concentration of the added derivatives.…”

“…above T iso the process with higher E a proceeds faster). 22,24 For example, oxidation of polyethylene inhibited by 1% C 60 -III is described by E a ¼ 120 kJ mol À1 and Z ¼ 1.2 Â 10 12 min À1 , giving the rate constants 1.85 Â 10 À5 min À1 at 100 C and 0.066 min À1 at 200 C. If 1% C 60 -IV is used, the kinetic parameters E a ¼ 148 kJ mol À1 and Z ¼ 3.7 Â 10 15 min À1 allow to calculate k 100 C ¼ 8.38 Â 10 À6 min À1 and k 200 C ¼ 0.193 min À1 . Thus, at 100 C C 60 -IV is more active than C 60 -III whereas at 200 C the derivative C 60 -III is more active than C 60 -IV.…”

Structure–Activity Relationships and Structural Design Optimization of a Series of p-Hydroxycinnamic Acids-Based Bis- and Trisphenols as Novel Sustainable Antiradical/Antioxidant Additives

“…In the past decade, there has been increasing demand on the part of both consumers and the industry for renewable nontoxic building blocks that could be used to replace fossil-based counterparts for the preparation of additives, polymers, and resins. − In this way, there have been various reports on the use of biobased phenolic functional polymers acting as flame retardants or antioxidants in polymer matrices. − …”

An Antioxidant Bioinspired Phenolic Polymer for Efficient Stabilization of Polyethylene

“…In the last few years, there has been an increasing demand on the part of consumers and the market for natural or renewable resource materials that could be used in the place of synthetic counterparts as building blocks for thermoplastic and thermosetting resins. − Several examples including the polymerization of natural monomers and their derivatives to obtain thermoplastic polymers with properties similar to those of commodity thermoplastics have been reported. − Furthermore, health and environmental concerns posed by the use of several chemicals involved in the synthesis of thermosets underscored the need for the development of a sustainable supply of biobased resins. − Interestingly, biobased phenolic functional polymers have been also described, acting as flame retardants or antioxidants when added in polymer matrices. − …”