Preventing thermal degradation of PVC insulation by mixtures of cross‐linking agents and antioxidants

Abstract

Poly(vinyl chloride) (PVC) is widely used—in spite of HCl formed from it at elevated temperatures. PVC wire and cable insulation has poor thermal stability, causing the plasticizer to separate from the PVC chains and produce an oily residue, lowering the tensile elongation at break and thus increasing brittleness. One uses cross‐linking agents and antioxidants, as well as mixtures of both, to improve the thermal stability of the plasticizer and tensile properties of PVC after thermal exposure. We performed tensile tests, tribological tests, profilometry, scanning electron microscopy (SEM), and water absorption determination before and after thermal exposure at 136 °C for 1 week. After adding the agents, elongation at break increased by 10 to 20% while the wear rate and water absorption were lower than for the control sample. Less voids are seen in the SEM images after adding these two kinds of agents. The thermal resistance of the PVC cable insulation is best enhanced by combinations of cross‐linking agents and antioxidants. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48816.

Thermal Stability of Nanosilica-Modified Poly(vinyl chloride)

“…This result indicates a highly advanced polymer degradation, i.e., a lower thermal stability of this compound, due to various composition of PVC R and PVC C compounds, particularly owed to the different type and loading of the thermal stabilizers. Analogous results of color changes were observed by Brostow et al [ 18 ] for the plasticized PVC as a function of radiation time.…”

“…The temperature higher than PVC softening temperature, i.e., above 150 °C, may induce several chemical reactions, such as dehydrochlorination, oxidation, and degradation. Particularly, due to the dehydrochlorination, the appearing double bonds may lead to color changes of the PVC samples; in this case, the yellowness was followed by dark red and finally by black color, an effect strongly dependent on heating time [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 17 , 18 , 23 , 25 , 26 , 27 , 36 , 37 , 39 ].…”

“…These explanations were confirmed by lightness measurements. The tests of color changes influenced by thermal degradation are often used in the case of assessment of stabilization efficiency of various PVC compositions [ 17 , 18 , 23 , 25 , 27 , 36 , 39 ].…”

“…The stabilizing effect of the new types of compounds with a capacity to improve the thermal stability of PVC, such as zinc urate, unsaturated maleic acid–sorbitol ester, and zinc maleic acid–sorbitol ester complex, as well as mannitol stearate ester-based aluminum alkoxide was also reported [ 15 , 16 , 17 ]. This effect is often synergistic with commercially used thermal stabilizers [ 15 , 16 ] and other additives used in PVC blends, such as cross-linking agents and antioxidants [ 18 ].…”

Effect of silane treated fly ash on physico‐mechanical, morphological, and thermal properties of recycled poly(vinyl chloride) composites

“…Although, most of the wires and cables are almost made up of poly(vinyl chloride) (PVC) material, which consists of 57% of chlorine 1 . PVC is significantly employed in wires and cables insulation or sheathing manufacturing as it has excellent self‐extinguishing properties 2 . It covers around 8% of PVC applications in cables and wires manufacturing industries.…”