Methoxyl Poly Research Articles

Effects of Br connected groups on atom transfer nitroxide radical coupling reaction and its application in the synthesis of comb‐like block copolymers

AbstractThe effects of Br connected groups on atom transfer nitroxide radical coupling (ATNRC) reaction were investigated. Two precursors methoxyl poly(ethylene oxide)‐b‐poly(ethylene oxide‐co‐2‐bromoiso butyryloxy glycidyl ether) (mPEO‐b‐Poly(EO‐co‐BiBGE)) and methoxyl poly(ethylene oxide)‐b‐poly(2‐bromoiso butyryloxy glycidyl ether) (mPEO‐b‐Poly(BiBGE)) with different C(CH3)2Br density were designed and synthesized firstly, and then ATNRC reaction were completed between these precursors and 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy poly(ε‐caprolactone) (TEMPO‐PCL) in the presence or absence of St monomers, respectively. The results showed that the structure of Br connected groups showed an important effect on ATNRC reaction, and the ATNRC reaction with high efficiency could be realized by transforming the higher active Br connected groups into the lower one by the addition of small amount of St monomers. The final comb‐like block copolymers mPEO‐b‐[Poly(EO‐co‐Gly)‐g‐(St1.8‐b‐PCL)] and mPEO‐b‐[Poly(Gly)‐g‐(St2.4‐b‐PCL)] with high coupling efficiency were obtained by this strategy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1633–1640, 2010

Synthesis and characterization of poly(methoxyl ethylene glycol-caprolactone- co-methacrylic acid- co-poly(ethylene glycol) methyl ether methacrylate) pH-sensitive hydrogel for delivery of dexamethasone

In this work, a novel pH-sensitive hydrogels based on macromonomer of methoxyl poly(ethylene glycol)–poly(caprolactone)-acryloyl chloride (MPEG-PCL-AC, PCE-AC), poly(ethylene glycol) methyl ether methacrylate (MPEGMA), and methacrylic acid (MAA) were successfully synthesized by heat-initiated free radical polymerization method. The obtained macromonomers and hydrogels were characterized by 1H NMR and FT-IR, respectively. Morphology study, swelling behavior, in vitro drug release behavior, acute oral toxicity of hydrogels, and cytotoxicity of PCE-AC macromonomer were also investigated in this paper. Finally, the hydrogels demonstrated that the sharp change in different pH value, thus believing to be promising the suitability of the candidate for oral drug-delivery systems.

Prostate cancer targeted MRI nanoprobe based on superparamagnetic iron oxide and copolymer of poly(ethylene glycol) and polyethyleneimin

Methoxyl poly (ethylene glycol) (mPEG-OH) was successfully grafted onto branched polyethyleneimine (hy-PEI) to yield a water soluble graft copolymer mPEG-g-PEI. This copolymer may package super-paramagnetic iron oxide (SPIO) by ligand exchange. The SPIO weight percentage in the polymer coated nanoparticles was determined to be 55%, the size and zeta potential of nanoparticles was 50 nm and 12 mV respectively. Antibody fixation onto the complex (mPEI-g-PEG-SPIO) surface layer was achieved by activated single chain monoclonal antibody against prostate stem cell antigen (PSCA). Our study showed that the single chain antibody functionalized nanoprobe (scAbPSCA-PEI-g-PEG-SPIO) with a small size can specifically enter the prostate cancer cells, decreasing MRI T2-weighted signal intensity of prostate cancer cells to 44.76%. Our results revealed that the potential of this magnetic nanoparticulate system promised as a novel MRI nanoprobe for early diagnosis of prostate cancer (PCa).

Amphiphilic graft copolymers based on ultrahigh molecular weight poly(styrene- alt-maleic anhydride) with poly(ethylene glycol) side chains for surface modification of polyethersulfone membranes

Amphiphilic graft copolymers having ultrahigh molecular weight poly(styrene- alt-maleic anhydride) (SMA) backbones and methoxyl poly(ethylene glycol) (MPEG) grafts were synthesized via the esterification between anhydride groups with hydroxyl groups. The synthesized graft copolymers, SMA- g-MPEGs, were used as additives in the preparation of polyethersulfone (PES) membranes via phase inversion process. X-ray photoelectron spectroscopy (XPS) analysis showed the comb-like graft copolymers spontaneously segregated to membrane surface during membrane formation. Water contact angle measurements and water absorbance experiments indicated the PES/SMA- g-MPEG blend membranes were much more hydrophilic than pure PES membrane. The blend membranes had stronger protein adsorption resistance than pure PES membrane did. After washed using de-ionized water for 25 days, the blend membranes exhibited higher hydrophilicity and stronger protein adsorption resistance. This phenomenon was attributed to the further accumulation of SMA- g-MPEG additives on membrane surface in aqueous conditions. SMA- g-MPEGs can be well preserved in membrane near-surface and not lost during membrane washing due to their high molecular weight and comb-like architecture.

Effects of comb copolymer PAA-g-MPEO on rheological and dispersion properties of aqueous CaCO3 suspensions

The comb copolymer poly(acrylic acid) (PAA) grafted methoxyl poly(ethylene oxide) (MPEO) (PAA-g-MPEO) as dispersant was used in aqueous CaCO3 suspensions. The PAA-g-MPEO was adsorbed onto CaCO3particle surfaces due to the electrostatic attraction. The adsorbed amount increased with increasing PAA-g-MPEO content. The CaCO3 adsorbed PAA-g-MPEO displayed negative zeta potential. The zeta potential was more negative with increasing PAA-g-MPEO content. Addition of PAA-g-MPEO, the conductivity of aqueous CaCO3 suspensions decreased firstly, and then increased with increasing PAA-g-MPEO content. Compared to that of aqueous CaCO3 suspensions, the viscosity of aqueous CaCO3/PAA-g-MPEO suspension reduced remarkably, and the liquidity of the suspensions was improved. The dispersion of CaCO3 particles in aqueous CaCO3/PAA-g-MPEO suspensions was significantly improved due to electrostatic repulsions and steric hindrance between CaCO3 particles adsorbed PAA-g-MPEO.