• Elastomers and Composites
• /
• v.48 no.1
• /
• pp.39-45
• /
• 2013

Melt grafting of citraconic acid (CCA) onto an ethylene-propylene-diene terpolymer (EPDM) with various peroxide initiators was performed using a Haake Rheocorder. Finding the optimum running condition and concentration is critical for effective grafting and performance of grafted material. Therefore, this study focused on the effects of mixing (reaction) condition and monomer/initiator dosages on the grafting degree, grafting efficiency and crosslinking degree (gel content), melt flow index and mechanical properties of CCA-g-EPDM. As the grafting degree/crosslinking degrees increased, the tensile strength increased significantly, but elongation at break and melt flow index decreased. The initiator 2,5-dimethyl-2,5-di(tert-butyl peroxy)-hexane (T-101) appeared to meet for the best grafting(2.31%). The grafting degree increased markedly with increasing monomer CCA/initiator T-101 contents. The grafting degree also increased with increasing mixing temperature/time, and then leveled off or decreased/increased a little. The optimum monomer/initiator dosages and reaction temperature/time were found to be about 5/0.05 wt% and $180^{\circ}C$/15min, respectively.

• Elastomers and Composites
• /
• v.58 no.3
• /
• pp.128-135
• /
• 2023

To improve the adhesive strength of natural rubber (NR) for a seismic isolation damper, citraconic acid-g-NR (CCA-g-NR) was synthesized via the melt grafting of citraconic acid (CCA) onto NR using an azobisisnomerobutyronitrile (AIBN) initiator. Subsequently, the influence of CCA and AIBN concentrations on the graft ratio G/R (%) and graft efficiency G/E (%) of the CCA-g-NR was investigated. The optimum CCA and AIBN concentrations required to achieve the desired G/R (3.49%) and G/E (49.8%) were found to be 7 phr and 0.13 phr, respectively. Additionally, we studied the influence of CCA-g-NR concentration on the mechanical properties (tensile strength, elongation at break, and modulus at 300%), adhesive strength, and cure characteristics of the rubber compound in the seismic isolation damper. As the concentration of CCA-g-NR increased, the elongation at break and adhesive strength of the compound increased, whereas its tensile strength and modulus at 300% decreased. Moreover, as the concentration increased, the maximum torque decreased and the scorch time was delayed to obtain an optimal vulcanization time.

• Korean Journal of Medicinal Crop Science
• /
• v.15 no.3
• /
• pp.143-147
• /
• 2007

The fruit flesh of four Prunus mume cultivated varieties, P. mume 'Nanko', P. mume 'Viridicalyx', P. mume 'Baigo', P. mume var, microcarpa 'Koshusaisho' Siebold & Zuccarni, were ground and extracted with ethyl acetate and their chemical components were analyzed by GC/MS-SIM. In the ten compounds which was used fer the calibration, maleic anhydride, citraconic anhydride, 5-hydroxymethylfurfural, vanillin, linoleic acid, ethyl linoleate, and squalene were determined in all the four cultivated varieties. However, palmitic acid was detected only in P. mume var. microcarpa 'Koshusaisho'. Isopropyl palmitate was found only in P. mume 'Baigo' and var, microcarpa 'Koshusaisho', while stearic acid was determined in P. mume 'Nanko', 'Viridicalyx', and var, microcarpa 'Koshusaisho'. In the variation of quantities, maleic anhydride was contained 245.4, 153.6, 20.1, and 2.7 ppm in P. mume 'Baigo', 'Nanko', var. microcarpa 'Koshusaisho', and 'Viridicalyx', respectively. Citraconic anhydride was also contained 637.4, 543.1, 150.7, and 38.7 ppm in P. mume 'Baigo', 'Nanko', var. microcarpa 'Koshusaisho', and 'Viridicalyx', respectively. The amounts of stearic acid were 105.5, 64.4, and 32.3 ppm in P. mume var. microcarpa 'Koshusaisho', 'Viridicalyx', and 'Nanko', respectively. Squalene was found in amounts of 7.6, 1.7, 1.0, and 0.5 ppm in P. mume var. microcarpa 'Koshusaisho', 'Baigo', 'Nanko', and 'Viridicalyx', respectively. The amounts of other minor compounds also were varied in the P. mume cultivated varieties.