Papers by Author: Nian Feng Han

Abstract: Hyperbranched polymer was prepared by the polycondensation reaction via the A₂+B₄ route. The polymer was obtained by the reaction of 1,3-tetramethyl-1,3-bis (methyl-dicholorosilyl) ethyl disiloxane and di-tert-butyl adipate. The obtained polymer was soft solid. The polymer was characterized by ¹HNMR and IR spectroscopies. The¹H NMR and IR analysis proved the existence of the branched structures in the polymer.

Abstract: Composite modified asphalts with micron fly ash/SBS and nanocalcium carbonate (nanoCaCO₃)/ SBS were prepared respectively by melt blending. The ageing properties and physical properties of micron fly ash/SBS and CaCO₃/SBS modified bitumen were investigated. The results demonstrate that micron fly ash/SBS modified bitumen exhibited an increasing softening point, a decreasing penetration and a decreasing ductility. Compared with that of SBS modified bitumen, the anti-aging property of the micron fly ash/SBS modified bitumen becomes worse. Effects of the nanoCaCO₃ on the properties of SBS modified asphalt appear as a decreasing penetration, an increasing softening point, and a decreasing ductility. The anti-aging property of the CaCO₃/SBS modified asphalt was better than that of the SBS modified asphalt.

Abstract: The polystyrene modified organophilic montmorillonite clays (PS-OMMT) were preparation through intercalating styrene monomer into the layer of OMMT by in-situ polymerization. Composite modified asphalts with PS-OMMT and SBS were prepared by melt blending. Results showed the interlayer spacing of OMMT was increased by the intercalated polymerization reaction of styrene. The modified OMMT and SBS homogeneously disperse in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Impact of the PS-OMMT on the properties of SBS modified asphalt appears as a decreasing penetration, an increasing softening point, and a decreasing ductility. Compared with that of SBS modified asphalt, the anti-aging property of PS-OMMT /SBS modified asphalt was greatly improved.

Abstract: Abstract. Micron fly ash/SBS modified bitumen composites were prepared by melt intercalation. The physical properties and ageing properties of micron fly ash/SBS modified bitumen were investigated. The results showed that micron fly ash/SBS modified bitumen exhibited a decreasing penetration, an increasing softening point, and a decreasing ductility. Compared with that of SBS modified bitumen, the anti-aging property of the micron fly ash/SBS modified bitumen becomes worse.

Abstract: Composite modified asphalts with nano calcium carbonate (nano CaCO3)/ SBS and nano montmorillonite (nano MMT)/SBS were prepared respectively by melt blending. Rolling thin film oven test (RTFOT) was carried out to study the aging properties. The results demonstrate that CaCO3/SBS and MMT/SBS homogeneously disperse in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Effects of the nano CaCO3 and nano MMT on the properties of SBS modified asphalt appear as a decreasing penetration, an increasing softening point, and a decreasing ductility. The anti-aging property of the nano MMT/SBS modified asphalt was better than that of the CaCO3/SBS modified asphalt and SBS modified asphalt.

Abstract: Organophilic montmorillonite (OMMT)/SBS modified bitumen composites were prepared by melt intercalation. The physical properties and ageing properties of OMMT/SBS modified bitumen were investigated. The results showed that OMMT/SBS modified bitumen exhibited a decreasing penetration, an increasing softening point, and a decreasing ductility. Compared with that of SBS modified bitumen, the OMMT /SBS modified bitumen can enhance the aging resistance of SBS modified bitumen.

Abstract: The PS-MMT was synthesized through intercalating styrene monomer into the layer of MMT by in-situ polymerization. Composite modified asphalts with PS-MMT and SBS were prepared by melt blending. Rolling thin film oven test (RTFOT) was carried out to study the aging property. The results demonstrate that both modified MMT and SBS homogeneously disperse in the base asphalt, which lead to an improvement in terms of toughness, strength, and thermal stability. Impact of the PS-MMT on the properties of SBS modified asphalt appears as a decreasing penetration, an increasing softening point, and a decreasing ductility. Compared with that of SBS modified asphalt, the anti-aging property of PS-MMT /SBS modified asphalt was greatly improved.

Abstract: Ethyl cellulose-graft-poly(N-isopropylacrylamide-co-6-[4-(4-ethoxyphenylazo)phenoxy] hexyl methacrylate) (EC-g-P(NIPAM-co-MAZO)) were synthesized through atom transfer radical polymerization (ATRP). Ethyl cellulose-based macroinitiator was prepared by direct acrylation of ethyl cellulose with excess 2-bromoisobutyryl bromide at room temperature, the bromo-ester groups of which were known to be efficient initiator for ATRP. Statistical copolymerization of N-isopropylacrylamide (NIPAM) and 6-[4-(4-ethoxyphenylazo)phenoxy] hexyl methacrylate (MAZO) onto ethyl cellulose (EC) was achieved using CuCl/Me6TREN as the catalyst system and N,N-dimethylformamide/water mixture (DMF/H2O, v/v = 4:1) as solvent. Appropriate solvent concentration and polymerization temperature can minimize the intermolecular coupling and render the polymerization controllable. The aggregates formed by EC-g-P (NIPAM-co-MAZO) copolymer in aqueous solution were investigated by varying temperature and irradiation under UV/visible light. The results indicated that the copolymer had thermal- and photo- dual-responsive properties. The copolymer formed a comparatively stable suspension in water at room temperature and underwent a hydrophilic-hydrophobic transition when the temperature raised. Furthermore, their aggregates in water were influenced by isomerization of azobenzene groups under UV/visible light irradiation.

Abstract: An azobenzene derivative substituted with a 2-bromoisobutyryl group was used as an initiator for the atom transfer radical polymerization of 2-[4-(4-ethoxyphenylazo)phenoxy]ethyl methacrylate) (MAZO). The resulting homopolymers (AZO-PMAZO) possess azobenzene moieties both in the main chain and in the side chain. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) preliminarily revealed the liquid crystalline property of these polymers. The novel liquid crystalline polymers are expected to act as the candidates in some promising areas including optical data storage, optical switch, and molecular devices.

Abstract: The new poly(silyl ester) has been prepared by the polycondensation reaction of 1,5-dichloro-1,1,5,5-tetramethyl-3,3-diphenyl-trisi1oxane with di-tert-butyl fumarate by the elimination of tert-butyl chloride as a driving force. To investigate the self-crosslinking reaction of the unsaturated poly(silyl ester), poly(1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane) was self- crosslinked in the presence of 2, 2'-azobis(isobutyronitri1e) (AIBN) as a radical initiator without solvent. After the self-crosslinking, the unsaturated poly(silyl ester), which was viscous liquids, turned into solid product. The characterization of the poly(silyl ester) and the self-crosslinked product included 1H-NMR spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Comparisons were made between the linear poly(silyl ester) and the self-crosslinked products. It was found that after crosslinking, the important resonance signal for ethenylene (C=C) of the poly(silyl ester) reduced, which show that the crosslinking reaction is carried out. The self-crosslinked product exist the structures of linear isomer and four-membered ring isomer. The glass-transition temperatures of the self-crosslinked poly(silyl ester) was higher than that of the uncrosslinked poly(silyl ester), and the thermal stability of the self-crosslinked poly(silyl ester) was better than that of uncrosslinked poly(silyl ester).