Ethylene–propylene–diene monomer (EPDM) rubber/samarium borate (SmBO3)/ethylene acrylic acid (EAA) and EPDM/sb in Sb-doped SnO2 (antimony tin oxide)/EAA composites are aged at 150°C for different intervals. It is found that alkaline SmBO3 can lower the oxidation rate of EPDM composites by scavenging acids formed during aging. The grown acrylic acid content lowers the pH level of EPDM composites and then elevates the oxidation rate. For EPDM/filler control, the chain scission dominates in the early stage of aging, while cross-linking takes the main effect in the latter stage of aging. Moreover, the poly (circular acid anhydride) formed by carboxylic acid in EAA during curing decomposes and influences the overall chemical cross-link points. The lowest crystallinity of EAA in EPDM/filler/EAA composites appears at the 10th day of aging and is attributed to the varied cross-link density. The changing trend of tensile strength is well consistent with that of swelling ratios, and electric properties are correlated with increased polar groups and crystallinity.
PremamoyGBibhaCAchintyaSK. Thermal and oxidative degradation of PE-EPDM blends vulcanized differently using sulfur accelerator systems. Eur Polym J1996; 32(8): 1015–1021.
2.
AllenRD. Fundamentals of compounding EPDM for cost/performance. J Elastomers Plast1983; 15(1): 19–32.
3.
RahimanHKUnnikrishnanGSujithA. Cure characteristics and mechanical properties of styrene-butadiene rubber/acrylonitrile butadiene rubber. Mater Lett2005; 59(6): 633–639.
4.
LemanceauSBertrand-ChadeyronGMahiouR. Synthesis and characterization of H-LnBO3 orthoborates (Ln 5La, Nd, Sm, and Eu). J Solid State Chem1999; 148(7): 229–235.
5.
ChenXC. Effect of oxalic acid on stabilization and property of Sb-doped tin oxide sol. J Sol-Gel Sci Technol2005; 34(6): 267–271.
6.
Abdel-BaryEMAbdel-RazikEAAbdelaalMY. Stability of polypropylene blends under the effect of thermal and UV degradation. Polym Plast Technol Eng2005; 44(5): 847–862.
7.
SantosoMSchusterRH. Investigations on initial stage of aging of tire rubbers by chemiluminescence spectroscopy. Rubber Chem Technol2007; 80(5): 785–802.
8.
ChenSJZhangJSuJ. Effect of damp-heat aging on the properties of ethylene-vinyl acetate copolymer and ethylene-acrylic acid copolymer blends. J Appl Polym Sci2009; 114(5): 3110–3117.
9.
WangWZQuBJ. Photo- and thermo-oxidative degradation of photocrosslinked ethylene-propylene-diene terpolymer. Polym Degrad Stab2003; 81(3): 531–537.
10.
EirichFR. Science and technology of rubber, New York: Academic Press, 1987.
11.
SuJChenSJZhangJ. Combined effect of pH level and surface treatment of Sm2O3, SmBO3 and ATO particles on cure, mechanical and electric properties of EPDM composites. Polym Test2009; 28(4): 419–427.
12.
SuJChenSJZhangJ. Comparison of cure, mechanical, electric properties of EPDM filled with Sm2O3 treated by different coupling agents. Polym Test2009; 28(3): 235–242.
13.
SuJChenSJZhangJ. Reinforcement of EPDM/SmBO3 and EPDM/ATO composites by three types of EAA: Assessment of AA content on crystallinity, cure, mechanical and electric properties. J Reinf Plast Compos2010; 29: 2946–2960.
14.
BrandrupJImmergutEHGrulkeEA. Polymer handbook, New York: Wiley-Interscience, 1999.
15.
TeissedreGPilichowskiJFChmelaS. Ageing of EPDM-I: Photo and thermal stability of EPDM hydroperoxides. Polym Degrad Stab1996; 53(2): 207–215.
16.
Morlat-TheriasSFantonETomerNSRanaSSinghRP. and Gardette J-L. Photooxidation of vulcanized EPDM/montmorillonite nanocomposites. Polym Degrad Stab2006; 91(12): 3033–3039.
17.
ChenSJZhangJSuJ. Effect of hot air aging on the properties of ethylene-vinyl acetate copolymer and ethylene-acrylic acid copolymer blends. J Appl Polym Sci2009; 112(3): 1166–1174.
18.
BikiarisDPrinosJPanayiotouC. Effect of EAA and starch on the thermooxidative degradation of LDPE. Polym Degrad Stab1997; 56(1): 1–9.
19.
Sen GuptaKKPalBSenPK. Kinetics and mechanism of the oxidation of some α-hydroxy acids by tetrachloroaurate(III) in acetic acid-sodium acetate buffer medium. Inter J Chem Kinet1999; 31: 873–882.
20.
MuasherMSainM. The efficacy of photostabilizers on the color change of wood filled plastic composites. Polym Degrad Stab2006; 91(5): 1156–1165.
21.
ChabiraSFSebaaMG’Sell C. Influence of climatic ageing on the mechanical properties and the microstructure of low-density polyethylene films. J Appl Polym Sci2008; 110(4): 2516–2524.
22.
SomrangNNithitanakulMGradyBP. Non-isothermal melt crystallization kinetics for ethylene-acrylic acid copolymers and ethylene-methyl acrylate-acrylic acid terpolymers. Eur Polym J2004; 40(4): 829–838.
23.
RogerAKennethTBrianaS. Monitoring the degradation of a thermally aged EPDM terpolymer by 1H NMR relaxation measurements of solvent swelled samples. Polymer2002; 43(4): 1349–1355.
24.
PunnarakPTantayanonSTangpasuthadolV. Dynamic vulcanization of reclaimed tire rubber and high density polyethylene blend. Polym Degrad Stab2006; 91(12): 3456–3462.
25.
TwomblyBShepardDD. Simultaneous dynamic mechanical analysis and dielectric analysis of polymers (DMA-DEA). Instrum Sci Technol1994; 22(3): 259–271.
26.
GeorgeSVarugheseKTThomasS. Dielectric properties of isotactic polypropylene/nitrile rubber blends: Effects of blend ratio, filler addition, and dynamic vulcanization. J Appl Polym Sci1999; 73(2): 255–270.
27.
DervosCTMergosJAIosifidesAA. Characterization of insulating particles by dielectric spectroscopy: Case study for CaCO3 powders. Mater Lett2005; 59(22): 2842–2849.
