The Use of Copper Oxides as Cross-Linking Substances for Chloroprene Rubber and Study of the Vulcanizates Properties. Part I

Abstract

The purpose of this work was to verify the ability to cross-link the chloroprene rubber (CR) by using copper oxides: copper(I) oxide or copper(II) oxide. The use of copper oxides arises from the need to limit the application of ZnO as a cross-linking agent of CR. The obtained results indicate that CR compositions cross-linked with copper oxides are characterized by good mechanical properties and a high cross-linking degree. The results show that the type and the amount of copper oxides influence the cross-linking of the CR and the properties of the vulcanizates. For compositions containing copper(II) oxide, the properties are linearly dependent on the amount of CuO. Such a relationship is difficult to notice in the case of the use of copper(I) oxide—when analyzing individual parameters, the best results are obtained for different samples. Infrared spectroscopy (IR) studies confirmed the possibility of cross-linking of chloroprene rubber with copper oxides. This is evidenced by the characteristic changes in the intensity of the bands. Structural changes in the material during heating were determined by the thermal analysis—differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Regardless of the type and amount of copper oxide, all compositions exhibit similar characteristics, and there are no significant changes in the glass transition temperature of the material.

The Use of Copper Oxides as Cross-Linking Substances for Chloroprene Rubber and Study of the Vulcanizates Properties. Part II. The Effect of Filler Type on the Properties of CR Products

“…A similar relationship can be observed in the case of CR cross-linked with CuO. The unfilled sample had a TS b value of 13.0 MPa [ 30 ]. The incorporation of chalk and MMT decreased TS b values to 9.03 MPa and 8.18 MPa, respectively.…”

“…The presented work is a continuation of previous research published [ 30 ]. Knowing the influence of the amount of copper(I) oxide and copper(II) oxide on the cross-linking of chloroprene rubber and the properties of vulcanizates, fillers were incorporated.…”

“…The tensile strength of the vulcanizates containing Cu 2 O was significantly reduced with the incorporation of chalk and MMT ( Table 4 , Figure 5 ). For the samples with these fillers, the TS b value was equal to 6.65 and 6.81 MPa, respectively, for chalk- and MMT-containing vulcanizates, while for the unfilled sample it was TS b = 13.5 MPa [ 30 ]. The vulcanizate containing silica was characterized by comparable strength to that for the unfilled vulcanizate ( TS b = 12.85 MPa), whereas the presence of kaolin or carbon black resulted in an increase in tensile strength (14.00 MPa and 18.87 MPa, respectively).…”

“…In our research, the elongation at the break for vulcanizates containing Cu 2 O was reduced due to the presence of fillers. For the unfilled sample, E b was equal to 752% [ 30 ]. The incorporation of chalk, kaolin, or MMT resulted in a slight reduction in E b to values from 708–713%.…”

“…Additionally, detailed investigations on the role of copper(I) oxide and copper(II) oxide as curing agents in CR compounds were thoroughly investigated. The effects of copper oxides on cross-linking and CR properties were described in detail in our earlier article [ 30 ]. This study will lead to a scientific understanding of how the type of copper oxide influences the properties of filled CR vulcanizates and will extend to being a source of useful information for preparing rubber products based on CR.…”