NBR/Zn(MAA)2/蒙脱土纳米复合材料的研究

研究NBR／基丙烯酸锌[Zn(MAA)2]／蒙脱土纳米复合材料的性能。结果表明，Zn(MAA)2可以通过原位聚合反应在与NBR发生接枝交联的同时，实现对蒙脱土的插层，用该方法制备的NBR／Zn(MAA)2／蒙脱土纳米复合材料的物理性能优异，含有有机改性蒙脱土HMMT和USM的复合材料性能更为突出，且具有一定的透明性。     

Development of pH-responsive poly(methylmethacrylate-co-methacrylic acid) membranes using scCO2 technology. Application to protein permeation

Porous membranes were developed in a two step process using supercritical CO₂ technology. Copolymers of methyl methacrylate (MMA) and methacrylic acid (MAA) were synthesized for the first time in supercritical carbon dioxide (scCO₂), being identified by ¹H NMR and FT-IR. The influence of the feed monomer ratio on their morphology, average molecular weight and T_g was studied. These PMMA-co-PMAA copolymers were then used in the preparation of thin pH-responsive membranes by scCO₂-assisted phase inversion method. The prepared films were characterized by scanning electron microscopy, mercury porosimetry, dynamical mechanical analysis, swelling and contact angle measurements, in order to study their morphology, pH-responsive character, hydrophilicity and viscoelastic properties by changing the monomer ratio composition of the copolymer from 5 to 50 wt% of MAA with respect to the total mass of monomers. PMMA-co-PMAA membranes were then tested for a potential application as protein filtration devices. Bovine serum albumin (BSA) was used as a model protein and permeation measurements were performed at three different pHs (4.5, 5.0 and 7.4). The PMMA–PMAA (90:10) membrane showed a good performance in terms of BSA amount filtrated, with distinct profiles at different pH, and consequently capable to assume an efficient role in protein filtration processes.     

三甲氧基丙烷三甲基丙烯酸酯合成工艺研究

本文阐述了以甲基丙烯酸与三羟甲基丙烷为原料合成三甲氧基丙烷三甲基丙烯酸酯的工艺.对影响酯化反应和精制的诸多因素进行了探讨;采用回归正交组合设计方法,得出优化组合的工艺条件.实验结果表明,三甲氧基丙烷三甲基丙烯酸酯的收率≥86%,纯度≥95%,获得满意的结果.     

The effects of pregrafting cotton fabrics with MAA/MAM on the dyeing kinetics of direct dyes in a finite bath

The influence of pregrafting of cotton fabrics with mixed monomer on the dyeing kinetics of direct dyes was investigated. The results of this research show that the equilibrium absorption (a_e) and activation energy (ΔE*) in the dyeing of grafted fabrics are smaller than those of ungrafted fabrics. The experimental results show that the value of the equilibrium absorption is smallest when the molar ratio of MAA/MAM (methacrylic acid/methylacryl amide) is 4/6. However, the rate constant (k′) is larger for grafted fabrics than for ungrafted fabrics. No significant difference was observed between the structural diffusion resistance constant (n) of grafted and ungrafted fabrics. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1139–1142, 1997     

Self-diffusion in Solutions of Carboxylated Acrylic Polymers as Studied by Pulsed Field Gradient NMR. 1. Solvent Diffusion Studies

The diffusion constants of solvent in solutions of carboxylated acrylic random copolymers in isopropanol (IPA) have been investigated using the PFG NMR technique. The copolymers are composed of butyl methacrylate and methacrylic acid with a range of molar ratios (BMA/MAA 100/0 through to 60/40 in 10 mol% steps). It was found that the echo attenuation function depended on the diffusion time, and experiments with short and long diffusion times have been analysed separately. Two questions are addressed: the first concerns the influence of concentration on the polymer aggregation in solution, and the second concerns the influence of the BMA/MAA molar ratio on the diffusion constants of the solvent. The data obtained have been discussed using established physical models for diffusion. Using the model of Wang gave the relative mass of bound solvent per mass of polymer which increased with the mol% of MAA in the copolymer.     

Mycosporine-like amino acid composition of the edible red alga, Palmaria palmata (dulse) harvested from the west and east coasts of Grand Manan Island,New Brunswick

The oxygen radical absorbance capacity (ORAC), antiproliferative activities and mycosporine-like amino acid (MAA) profiles of methanol extracts from two grades of dulse harvested from locations varying in UV-exposure (west vs east coasts of Grand Manan Island, NB) were determined in the present study. MAAs confirmed by LC/MS in both grades 1 (low-UV) and 2 (high-UV) dulse were palythine, shinorine, asterina-330, palythinol and porphyra-334; usujirene was present only in grade 2 dulse. ORAC values of grade 1 and 2 dulse extracts were 36.42 and 38.78 μmol Trolox/g extract. B16-F1 murine skin melanoma cell proliferation was inhibited (p < .05) by 68.5% and 91.9% by grade 1 and 2 dulse extracts at 6.0 mg/mL. The antiproliferative efficacy of grade 2 dulse was greater (p < .05) than grade 1 from 0.375 to 6.0 mg/mL. MAA differences between the grade 1 and 2 dulse extracts likely influenced the antiproliferative efficacies, despite the similar ORAC values.     

Effect of Poly (Ethylene Glycol) Molecular Weight and Microparticle Size on Oral Insulin Delivery from P(MAA‐g‐EG) Microparticles

Five years of successful work in our lab have shown that graft copolymer networks of poly(methacrylic acid‐g‐ethylene) [P(MAA‐g‐EG)], are very promising candidates for oral drug delivery. In an acidic environment, these copolymers form interpolymer complexes, protecting the active agent from the harsh environment of the gastrointestinal tract. At high pH, these complexes dissociate, causing the polymer to swell and release the drug. Films of P(MAA‐g‐EG) with a monomer ratio of 1:1 (MAA:EG) were prepared by free radical solution UV‐polymerization, washed in order to remove the unreacted monomer, and crushed to form microparticles with different particle size distribution. Previous studies in our lab have focused on using polymer disks in their swelling studies. The swelling properties of polymer disks vs. crushed particles were investigated via equilibrium swelling experiments in this study. Another goal in this study is to compare different PEG chain length (MW‐400 and MW‐1000) and different particle size (150–212 microns, 90–150 microns and 25–90 microns) in their loading and release behavior. After 6 hours of exposing the polymer with the insulin solution we achieved approximately 90% of insulin loading.     

Amphiphilic and biocompatible properties of poly (EA‐MAA)

The amphiphilic and biocompatible behaviors of Poly (acetate‐methylacrylic acid) Poly(EA‐MAA) were investigated in this study. The aggregation behavior of Poly(EA‐MAA) in aqueous media was investigated by steady‐state fluorescence spectroscopy and surface tensiometry. The critical aggregation concentration (cac) of Poly(EA‐MAA) was determined to be ～0.03 mg/mL. Ultraviolet spectrum (UV) and fluorescence spectrum results indicated that there are interactions form between Poly(EA‐MAA) and bovine serum albumin (BSA). And β‐sheet can be changed into α‐helix of BSA in Poly(EA‐MAA) solution effectively revealed by Circular dichroism (CD), which is driven by the H‐bond and hydrophobic interactions. The good cell‐compatibility of Poly(EA‐MAA) makes it great potential in the biomedical fields. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and characterization of micron‐sized magnetic microspheres by one‐step suspension polymerization

Micron‐sized magnetic microspheres with different functional groups were prepared by one‐step suspension copolymerization of styrene, divinyl benzene, and methyl methacrylate in the presence of oleic acid‐coated magnetic nanoparticles. In the present work, we used benzoyl peroxide as an initiator and poly(vinyl alcohol) (PVA‐1788; degree of polymerization: 1,700; degree of hydrolysis: 88%) as a stabilizer. We also added acrylamide (AM) monomer in the aqueous phase and methacrylic acid (MAA) in the oil phase. The morphology and properties of the resulting magnetic microspheres were examined by optical micrographs (OMs), vibrating‐sample magnetometer (VSM), and Fourier transform infrared spectrometer (FT IR). The results showed the three products have uniform and spherical form with superparamagnetism and well dispersion. Moreover, we found that monomer AM had a little contribution to the copolymerization, and MAA could strikingly decrease the diameter of the final microspheres. The magnetic microspheres with functional groups could be linked well with the IgG‐FITC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Zn(AA)2与Zn(MAA)2并用对EPDM硫化胶性能影响

本文研究了丙烯酸锌[Zn(AA)2]与甲基丙烯酸锌[Zn(MAA)2]并用对三元乙丙橡胶(EPDM)物理机械性能的影响。实验结果表明：Zn(AA）2与Zn(MAA)2并用对EPDM性能的影响不产生协同效应，Zn(AA)2对提高EPDM硫化胶物理力学性能和与金属的粘合强度比Zn(MAA)2有更显著的效果，Zn(AA)2的用量在4—5份时即可取得较好的粘合强度。