Preparation and Anti-ultraviolet Aging Performance of Organic Layered Double Hydroxides/Bitumen Composites

Layered double hydroxides (LDHs) with the physical property of high ultraviolet (UV) reflectance were used to enhance the anti-UV aging performance of bitumen. In view of the poor compatibility of LDHs with bitumen, three organic anions, namely, sodium dodecyl benzenesulfonate (SDBS), sodium dodecyl sulfate (SDS) and sodium dodecyl sulfonate (SDSO), were used as modifiers to prepare organic LDHs (OCLDHs) through regeneration process, and the crystal structure, chemical composition, morphological feature and UV shielding capability of synthesized OCLDHs were analyzed. Then the OCLDHs were added into bitumen to evaluate the storage stability and anti-UV aging property of OCLDHs/bitumen composites. The results show that the organic anions are inserted into the interlayers of LDHs, the intercalation expands the interlayer distance of LDHs, makes the particle shapes become more irregular and complicated, and enhances the absorption ability within the range from 200 to 300 nm while has little influence on the UV reflection ability. Result of high temperature storage stability indicates the organic modification ameliorates the compatibility of LDHs with bitumen. Compared with LDHs, OCLDHs decrease the deteriorations of bitumen's properties during UV exposure test, exhibiting better effect in enhancing anti-UV aging performance of bitumen. Furthermore, among the three OCLDHs, LDHs intercalated by SDBS exhibit the most effective improvement due to the best compatibility with bitumen and comparatively good UV shielding effect.