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A series of copolymers of ethylene with 1-hexene synthesized using a metallocene catalyst are selected and mixed. The blend is fractionated via preparative temperature rising elution fractionation (P-TREF). All fractions are characterized via high-temperature gel permeation chromatography (GPC), 13C nuclear magnetic resonance spectroscopy (13C-NMR), and differential scanning calorimetry (DSC). The changes in the DSC melting peak temperatures of the fractions from P-TREF as a function of elution temperature are almost linear, thereby providing a reference through which the elution temperature of TREF experiments could be selected. Moreover, the standard calibration curve (ethylene/1-hexene) of P-TREF is established, which relates to the degree of short-chain branching of the fractions. The standard calibration curve of P-TREF is beneficial to study on the complicated branching structure of polyethylene. A convenient method for selecting the fractionation temperature for TREF experiments is elaborated. The polyethylene sample is fractionated via successive self-nucleation and annealing (SSA) thermal fractionation. A multiple-melting endotherm is obtained through the final DSC heating scan for the sample after SSA thermal fractionation. A series of fractionation temperatures are then selected through the relationship between the DSC melting peak temperature and TREF elution temperature.

Hydroxyethyl chitosan （HE-chitosan） is a water-soluble derivative of chitosan with many apparent biological properties. For example, it is non-toxic and rapidly biodegradable. Moreover, HE-chitosan has advantages in water-solubility, moisture retention and gelling property due to its hydroxyethyl group. However, the biocompatibility and biodegradability of this multifimctional de- rivative have rarely been documented although they are critical for its application in biomedical and clinical treatments. The purpose of this work was to evaluate the biosafety of HE-chitosan, and draw important clues for its diverse applications. HE-chitosan was synthesized and characterized its chemical structure with FTIR. Its molecular weight （Mw） was determined by gel permeation chro- matography （GPC）, and its deacetylation degree （DD） was investigated through potentiometric analysis. The cytotoxicity of HE-chitosan on mouse fibroblast cell L929 was tested. The biocompatibility and biodegradability of HE-chitosan in rat and rabbit were evaluated. The FTIR results indicated that the hydroxyethyl groups were linked to C6 of chitosan. The GPC analysis confirmed that its Mw was about 90.01 kDa. It was also demonstrated that HE-chitosan had excellent biocompatibility and biodegradability in vivo and had no cytotoxicity on L929. These findings indicated that HE-chitosan can potentially be applied as a biomaterial in tissue engineering, drug delivery, and other biomedical fields.

Monomer of 7-methacryloyloxy-4-methylcoumarin (MAOMC) was synthesized and characterized by FTIR, 1H-NMR and 13C-NMR spectroscopy. Copolymers of MAOMC with butoxyethylmethacrylate (BOEMA) at different feed compositions were prepared by free radical solution polymerization at (70 ± 1) °C in ethylmethylketone (EMK) using benzyl peroxide (BPO) as an initiator. The copolymers were characterized by FTIR and 1H-NMR spectroscopy. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of the copolymers showed moderate thermal stability and higher Tg values. Gel permeation chromatography (GPC) was used to find out the molecular weights of the different copolymers. Antibacterial activities of the copolymers were also investigated against the selected pathogenic bacteria’s. The antibacterial activity of the copolymer increases as the MAOMC content increases in the copolymer. This shows that coumarin moiety plays a very important role in the antibacterial activity.

We describe in this work an alkyne-hydrosilylation approach to synthesize a series of novel polysiloxane side-chain LCPs attaching end-on or side-on mesogenic side groups. Their properties are characterized by NMR, FTIR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarized optical microscopy and small-angle X-ray scattering. These obtained alkenylsilane linked novel LCPs exhibit higher glass transition temperatures and clearing points, and especially display the tendency of forming smectic phases, in strong contrast with the nematic phases of their comparative conventional alkylsilane linked analogues, which manifests more rigid features of the alkenylsilane linkages and their significant influence on the mesomorphic properties.

The moisture aging effect and mechanism of asphalt binder during the in-service life of pavement were investigated by laboratory simulating tests.Pressure aging vessel（PAV） test simulating the long-term aging of binder during the in-service life of pavement was modified to capture the long-term moisture aging effect of binder.Penetration grade tests including penetration test,soften point test,and ductility test as well as SuperpaveTM performance grade tests including viscosity test,dynamic shear rheometer test,and bending beam rheometer test were conducted to fully evaluate the moisture aging effect of binder.Fourier transform infrared spectroscopy test and Gel-permeation chromatography test were applied to provide a fundamental understanding of the moisture aging mechanism of binder.The results indicate that moisture condition can accelerate the aging of asphalt binder and shorten the service life of asphalt binder.The modified PAV test with moisture condition can well characterize the moisture aging properties of asphalt binder.

A low-density polyethylene (LDPE) resin with excellent processing and film-forming properties is fractionated through temperature rising elution fractionation (TREF) technique. The chain structures of both the original resin and its fractions are further analyzed using high-temperature gel permeation chromatography (GPC) coupled with triple detectors (refractive index (RI)-light scattering (LS)-viscometer (VIS)), 13C-nuclear magnetic resonance spectroscopy (13C-NMR), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and successive self-nucleation/annealing (SSA) thermal fractionation. The 13C-NMR results show that the original resin has both short chain branch (SCB) (2.82 mol%) and long chain branch (LCB) (0.52 mol%) structures. The FTIR results indicate that the methyl numbers (per 1000 C) of the fractions gradually decrease from 81 to 46 with increasing elution temperature from 25 °C to 75 °C. The TREF-GPC cross-fractionation results show that the main component is collected at around 68 °C. The molecular weight of the components in the high elution temperatures of 60 °C to 75 °C is from 2.0 × 103 g/mol to 2.0 × 106 g/mol, and the relative amount is more than 80%. In the low elution temperature region below 50 °C, the molecular weights of the components range from 1.0 × 103 g/mol to 1.6 × 104 g/mol, and the relative amount is less than 10%. In the DSC results, the melting peaks of the fractions gradually increase from 80.1 °C to 108.8 °C with elution temperature. In the SSA thermal fractionation, each resin fraction shows a broad range of endotherm with multiple melting peaks (more than eight peaks). The melting peaks shift toward high temperatures with the elution temperature. The characteristic chain microstructure for the resin is also discussed in detail.

A Novel thermosensitive dendritic copolymer based on polyethylene glycol (PEG) and poly(N-isopropylacrylamide) (PNIPAm) with a cloud point (CP) around 36 °C was successfully synthesized by preparation of a dendritic polyol and followed by atom transfer radical polymerization (ATRP) of N-isopropylacrylamide. The dendritic copolymer was characterized using gel-permeation chromatography (GPC), FTIR and 1H-NMR spectroscopy. The self-association behavior of the copolymer in aqueous medium was investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). These investigations confirmed that the dendritic copolymer showed different association behaviors at various temperatures.

A facile, safe and economical reducing agent, sodium hypophosphite (NaH2PO2·H2O), has been successfully employed for ambient temperature living radical copolymerization of styrene (St) and methyl methacrylate (MMA). Such effective reducing agent significantly improved the reactivity of low reactive St monomers during the copolymerization, where the reactivity ratios of St and MMA were determined to be 0.50 and 0.36 by Finemann-Ross method. Thus the copolymerizations proceeded fast and showed typical living/controlled features, as evidenced by pseudo first-order kinetics of polymerization, linear increase in molecular weight versus monomer conversion, and low polydispersity index values. Effects of the concentration of reducing agent and the monomer feed ratio on the copolymerization were investigated in detail. Furthermore, gel permeation chromatography and 1H-NMR analyses as well as chain extension experiments confirmed the high chain-end functionality of the resultant copolymer.

A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin, which were prepared by the radical addition-fraction transfer (RAFT) method and characterized by the gel-permeation chromatography (GPC) and 1H-NMR. And the self-assemblies of these block copolymers with various chain length ratios in the different concentrations in CHCl3 were stable according to the results of DLS and TEM. Additionally, it was also given an insight investigation on the regulation of self-assembly of the block copolymers by adding dibutyltin dichloride and a possible mechanism was proposed.

A series of novel copolymers were successfully synthesized by ring-opening polymerization （ROP） of 3 （S）-methyl-morpholine-2,5-dione （MMD） and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one （MBC） using stan- nous octoate as catalyst. The copolymers were characterized by means of ~H-NMR and FT-IR spectroscopy. Gel permeation chromatography （GPC） test shows that the average-number relative molecular mass and average-weight rela- tive molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry （DSC） demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.