Papers by Author: De Jie Zhou

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: 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).

Abstract: The unsaturated poly(silyl ester) has been prepared by the polycondensation reaction of 1, 3-dichloro-tetramethyldisiloxane with di-tert-butyl fumarate. To investigate the crosslinking reaction of the unsaturated poly(silyl ester), poly(tetramethyl disilyloxyl fumarate) was self-crosslinked and cocrosslinked with styrene in the presence of 2, 2'-azobis(isobutyronitri1e) (AIBN) as a radical initiator. After the crosslinking, the unsaturated poly(silyl ester)s, which were viscous liquids, turned into solid products. The characterization of the poly(silyl ester) and the crosslinked product included infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Comparisons were made between the linear poly(silyl ester) and the crosslinked products. It was found that after crosslinking, the important resonance signal for ethenylene (C=C) of the poly(silyl ester) disappeared, which show that the crosslinking reaction is carried out progressively. The glass-transition temperatures of the self-crosslinked and cocrosslinked product were higher than that of the uncrosslinked poly(silyl ester), and the thermal stability of the crosslinked poly(silyl ester)s was better than that of uncrosslinked poly(silyl ester). In degradation tests, the self-crosslinked product degradable completely in 35 minutes and the cocrosslinked product complete mass loss in 5 days and the release of PNA followed the degradation of the crsslinked product. The rate of degradation of the poly(silyl ester) decreased after the crosslinking.

Abstract: Photo- and temperature-responsive amphiphilic block copolymers, poly(ethylene glycol)-b-poly{(N-isopropylacrylamide-co-6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate), denoed as PEO-b-P(NIPAM-co-MAZO), were designed and synthesized by atom transfer radical polymerization (ATRP). The macroinitiator based on poly(ethylene glycol) (PEG, Mn = 2000 Da) was utilized to initiate the copolymerization of N-isopropylacrylamide (NIPAM) and 6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate (MAZO). The resultant copolymers, combining photo-responsive moieties with thermal-responsive moieties, possess photo- and temperature- dual-responsive property, among of which, PNIPAM shows lower critical solution temperature (LCST) and PMAZO exhibits reversible trans-cis isomerization under UV/vis irradiation. In selective solution they can form selective micro-tunnel with excellent controlled release, and can be used as drug carrier and controllable membrane.

Abstract: Atom transfer radical polymerization (ATRP) has been employed for the synthesis of a novel amphiphilic fluorinated triblock copolymer PEG-b-PS-b-PFHEM for anti-fouling coatings. The macroinitiator based on poly(ethylene oxide) monomethyl ether was used to prepare an amphiphilic diblock copolymer PEG-b-PSt-Br, which was then utilized to initiate the ATRP of fluorinated monomer perfluorohexylethyl acrylate (FHEA), resulting in an amphiphilic triblock copolymer. These copolymers were characterized by means of 1H NMR and GPC. The amphiphilic triblock copolymer surface composes of fluorinated and PEGylated blocks, and the fluorinated surface has critical surface energy, while the PEGylated surface is expected to have a relatively low interfacial energy when in contact with water. Microphase-separation of both blocks could take place and result in the reduction of protein adsorption and cell adhesion. The amphiphilic fluoropolymer has the potential application as excellent antifouling coatings and antifouling membranes.