| Because of the rise of the oil price and the depleting of coal industry in recent years, developing alternative renewable bio-based polymer materials has been put on the research agenda. According to the past studies of our group, a novel biobased polyester elastomer (BPE) has been synthesised by polymerizing several commercial biobaesd monomers, which exhibits good biocompatibility, elasticity and mechanical properties after being nano-enhanced. BPE has saturated polar ester group as repeat units in the main chain of the molecule and unsaturated double bond in its side chain. Therefore, BPE nanocomposite is expected to have good oil resistance and thermal aging property. What’s more, BPE elastomer molecules are very flexible and it is expected to have good low temperature performance. Accordingly, we optimized the processing craft of BPE and studied the above mentioned properties, including the aging properties and the aging mechanism, oil resistance properties of BPE. The low temperature properties was studied and improved as well.In this thesis, we studied the aging behavior changes firstly. Both aging behavior changes and aging mechanism were investigated in this paper (chapter3). The mechanical properties of BPE/CB nanocomposites were found to decrease gradually as the aging time and temperature increase in essence, but still stayed at a high level. BPE/CB nanocomposites exhibited good anti-aging properties. Furthermore, the aging mechanism was detected by fourier transform infrared spectroscopy (FTIR)、differential scanning calorimetry (DSC) and the crosslink density changes of BPE during aging. A plausible aging mechanism of BPE was proposed. It can be concluded that the thermal oxidation process gives priority to further crosslinking in the initial period of aging. As the aging time increases, chain scission becomes the dominant element in the subsequent thermal oxidation process.In this thesis, the oil resistance property of BPE/CB nanocomposites was studied secondly (chapter4). After soaking in three kind of oil in the room temperature environment, the retention rate of mechanical properties of BPE reached91.6%、93.3%and80.1%, respectively. It turned out that compared with NBR,the retention rate of mechanical properties of BPE/CB nanocomposites and NBR/CB nanocomposites were basically flat below100℃while the retention rate of mechanical properties of BPE/CB nanocomposites was higher than that of NBR/CB nanocomposites by temperatures above100℃.Finally, the low temperature property of BPE/CB nanocomposites was studied for the first time (chapter5). We prepared a new kind of pentamer bio-based polyester elastomer without crystal for the first time by changing the synthetic recipe for the BPE raw rubber. Its low temperature brittleness can reach-55℃and the compression coefficient is0.21at a low environmental temperature of-50℃, showing that new BPE/CB nanocomposites can maintain high strength, impact resistance and good flexibility at low temperature. |
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