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Polyurethane (PU) and polyurea (PUA) materials have shown significant potential for application in tissue repair. Herein, we design a glycerol ethoxylate (PEG)-based poly(urethane-urea) for bone tissue repair. The polymer precursor was prepared from the reaction of PEG and isophorone diisocyanate (IPDI). The cystine dimethyl ester was used as a cross-linker for the preparation of poly(urethane-urea) elastomers. The material was further strengthened by physical blending of nano-hydroxyapatite (nHA). The physical and biological properties of final material were evaluated by mechanical testing, scanning electron microscopy characterization, degradation tests, cell proliferation and cell differentiation assays. The obtained scaffolds showed good mechanical strength, excellent biocompatibility and osteogenic capability. All the evidences demonstrated that this type of materials has good prospects for bone tissue repair application. [ABSTRACT FROM AUTHOR]

Initiated by tetraethylthiuram disulfide, the solution polymerization of a new monomer, 2-(4-vinyl-benzyloxy)-naphthalene (VBN), which had naphthalene chromophore was successfully conducted in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO). While using benzoyl peroxide as initiator, the polymerization was out of control under equal conditions. The poly(2-(4-vinl-benzyloxy)-naphthalene) (PVBN) and copolymer of VBN and styrene (poly(VBN-co-St)) had strong fluorescence emission at 350 nm, excited at 274 nm. Although the polystyrene (PS) had no fluorescence emission excited at 274 nm, the fluorescence intensities of poly(VBN-co-St) were enhanced with the increase of styrene feed ratio. [ABSTRACT FROM PUBLISHER]

In this report, the photo and thermo dual responsive block copolymer, PVHMA-b-PNIPAM, is synthesized by reversible addition-fragmentation chain transfer polymerization. The structure of copolymer was characterized by GPC and NMR. The copolymer trends to form micelles in water. A photo controlled reversible size changing as well as temperature induced reversible precipitation and dispersion in water was found. [ABSTRACT FROM PUBLISHER]

Here, we reported the synthesis of branched poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) via a combination of activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) and self-condensing vinyl polymerization (SCVP) techniques. The typical linear kinetics of the AGET ATRP of DMAEMA with the initiation of 2-(2-bromoisobutyryloxy) ethyl methacrylate (BIEM) was observed. The molecular weight (Mn ) of the branched PDMAEMA increased with the monomer conversion. The GPC traces of these polymers were unimodal and the molecular weight distributions (Mw/Mn ) were in the range of 1.30–2.10. The degree of branching (DB) determined by NMR spectra agreed with theoretical value. The branched amphiphilic copolymer functionalized with azobenzene was then prepared via AGET ATRP chain-extension of branched PDMAEMA with azobenzene monomer, 6-[4-(4-methoxyphenylazo)phenoxy]hexyl(meth)acrylate as the second monomer. The GPC traces of these branched copolymers showed the mono-peaks, which proved the successful preparation of copolymers. The properties of this branched copolymer in controlling drug release were also investigated. It was found that the drug release rate of chlorambucil can be controlled by various factors, such as polymer structure, light, temperature and pH values. [ABSTRACT FROM PUBLISHER]

Poly(tert-butyl acrylate) (PtBA) bruhes were successfully grafted on the cellulose filter papers via surface-initiated atom transfer radical polymerization (ATRP). Then the grafting PtBA brushes were transferred into poly(acrylic acid) (PAA) in the presence of trifluoroactic acid (TFA), which can form chelate complexes with Ag+. The Ag+ was reduced in situ to obtain the silver nanoparticles decorated cellulose filter papers. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to characterize the chemical structure of the resulting product. The morphologies of the filter paper at different stages of surface modification were investigated by field emission scanning electron microscopy (FESEM). The silver nanoparticles decorated filter paper performed good antibacterial ability against E. coli as compared with the original filter paper and PAA modified filter paper. [ABSTRACT FROM AUTHOR]

One linear and two miktoarm star side-chain liquid crystalline (LC) block copolymers with p-methoxyazobenzene moieties were prepared by a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) techniques. First, ROPs of ε -caprolactone (ε -CL) were carried out catalyzed by Sn(Oct)2 using three multifunctional initiators, hydroxyethyl 2-bromoisobutyrate (AB type), 3-hydroxy-2-(hydroxymethyl)-2-methylpropyl 2-bromo-2-methylpropanoate (A2B type) and 2,2-bis(hydroxymethyl)propane-1,3-diyl bis(2-bromo-2-methylpropanoate) (A2B2 type), at 110°C in toluene, respectively. Second, the previously obtained poly(ε -caprolactone)s (PCLs) with bromines functionalities were used as the macroinitiators to conduct ATRP of 6-(4-methoxy-4-oxy-azobenzene) hexyl methacrylate (MMAZO) with CuBr/PMDETA as the catalyst systems at 85°C in anisole to prepare the linear and miktoarm side-chain LC block copolymers (PCL-b-PMMAZO, (PCL)2-(PMMAZO) and (PCL)2-(PMMAZO)2). The produced polymers were well-controlled with the controlled molecular weights and the relatively narrow molecular weight distributions (Mw/Mn ≤ 1.35). The structures of the obtained polymers were all characterized by NMR, FT-IR and GPC analysis. Furthermore, the LC properties of the linear and miktoarm star block copolymers were also investigated by differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). [ABSTRACT FROM AUTHOR]