POLYMER INTERNATIONAL
·
2020
·Vol. 70
·期 2
·185-192
·
IF 2.574
Yuanyuan Hou,Fei Huang,Hui Yang,Hao Cong,Xi Zhang,Xiaoxu Xie,Haibo Yang,Qiuping Tong,Ning Luo,Ping Zhu,Jianzong Meng
Levansucrase (EC 2.4.1.10) catalyzes both levan polymerization and sucrose hydrolysis. Levan production by recombinant Bacillus subtilis levansucrase SacB-T305A was investigated. The maximum conversion yield (33.09%) of sucrose to levan and levan yield (115.8 g L –1 ) were obtained as 30% (wt/vol) and 40% (wt/vol) initial sucrose, respectively. Under highly acidic conditions (pH 3.5 and below), the polymerization not only shifted distinctly to high molecular weight levan but also enlarged the size of low molecular weight levan. In particular, the proportion of high molecular weight levan to total products increased to 9-fold at pH 3.5. The presence of Fe 2+ , Mg 2+ , Mn 2+ and Zn 2+ ions at common ion strength (5 mmol L –1 ) increased only the size of low molecular weight levan from about 20 kDa to about 35 kDa. Our findings provide a supplementary view about the mechanism of levan molecular weight distribution in enzymatic synthesis and offer a possibility for producing levan of different molecular weights by modulating enzymatic reaction conditions. © 2020 Society of Industrial Chemistry
研究领域:
生物化学
·
工业微生物学
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2021
·Vol. 71
·期 3
·317-327
·
IF 2.99
Wenjie Song,Junwu Wei,Lindong Li,Yangyang Qian,Yujia Wang,Yunmei Bi
In this study, two linear poly( N -vinylcaprolactam)s (PNVCLs) with different molecular weights were first synthesized as polymeric supporters by reversible addition-fragmentation chain transfer polymerization and then were used to prepare cathepsin B and thermal dual-stimuli responsive amphiphilic linear–dendritic block copolymers (LDBCs) PNVCL n - b - d (Phe-Lys) 1–3 ( n = 66, 100) with linear PNVCL and dendritic phenylalanyl-lysine (Phe-Lys) dipeptides via stepwise peptide chemistry. The copolymers were characterized by 1 H NMR spectra and gel permeation chromatography and exhibited a controlled molecular weight and a narrow molecular weight distribution (polydispersity index ≤ 1.27). They self-assemble into stable micelles at relatively low critical micelle concentrations (0.007–0.019 mg mL −1 ) in aqueous solution. These micelles are capable of dissociating to release the encapsulated anticancer drug doxorubicin upon cathepsin B treatment. The doxorubicin release rates from PNVCL n - b - d (Phe-Lys) 1–3 micelles decreased with increasing generation of Phe-Lys dipeptide dendrons and decreasing molecular weight of PNVCL. In addition, the lower critical solution temperatures of the copolymers increased with an extension of the enzyme incubation time. The results of in vitro cytotoxicity and cell uptake experiments showed that LDBCs show no cytotoxicity even at a high LDBC concentration of 0.4 mg mL −1 and the drug-loaded micelles can be enriched in tumor cells. Such smart copolymers could be efficiently used in targeted therapy systems. © 2021 Society of Industrial Chemistry.
研究领域:
生物材料
·
药学
·
肿瘤学
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2019
·Vol. 69
·期 3
·228-238
·
IF 2.433
Jing-hui Yang,Ting-ting Zhang,Yong-sheng Zhang,Nan Zhang,Ting Huang,Yong Wang
Carbon nanotubes (CNTs) and barium titanate (BaTiO 3 ) (BT) were simultaneously introduced into the immiscible blend poly(ethylene- co -vinyl acetate)/thermoplastic urethane (EVA/TPU), and the EVA/TPU/CNT/BT quaternary polymer composite blends with core–shell structured island TPU domain were successfully prepared, in which CNTs in the TPU domain act as the core and the BT spheres at the interface of the TPU and EVA act as the shell. A core–shell structured island can lead to the formation of micro-capacitors and further accumulate electron storage owing to the incorporation of CNTs and BT; on the other hand, a BT shell can be assembled along the TPU spheres, reducing the possibility of formation of a conductive CNT network, resulting in suppressed dielectric loss. Therefore, CNTs and BT were tailor-made into blend composites with a core–shell structured domain, which can achieve an increased dielectric constant by 176% and decreased low dielectric loss by 80% compared with the blend composites with only CNTs in the TPU domain. © 2019 Society of Chemical Industry
研究领域:
材料科学
·
高分子化学
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2011
·Vol. 60
·期 9
·1287-1290
·
IF 2.056
Qingquan Liu,Yingxiang Duan,Shaohua Shen,Zhihua Zhou
Pomegranate-like polystyrene-based microspheres with high porosity were successfully prepared via a simple route involving two steps. The first step was the preparation of polystyrene-based microspheres with multi-cores and a non-porous shell via suspension polymerization of divinylbenzene and vinylbenzyl chloride. Nitrogen sorption failed to characterize the pore structure of the microspheres because of the non-porous shell, but the results of Hg intrusion indicated that the pore volume of the microspheres was 0.36 cm 3 g −1 . The second step was post crosslinking of the microspheres derived from the first step. Extensive porosity was generated in the shell and the pomegranate-like structure of the microspheres remained almost unchanged. The results showed that the pore volumes of the final products derived from N 2 sorption and Hg intrusion were 0.54 cm 3 g −1 and 0.66 cm 3 g −1 , respectively. Overall, this provides a simple and feasible route to biomimetic preparation of pomegranate-like polystyrene-based microspheres with high porosity. Copyright © 2011 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2018
·Vol. 67
·期 11
·1545-1554
·
IF 2.352
Keping Chen,Fen Cao,Shuen Liang,Jianhua Wang,Chunrong Tian
Poly(ethylene oxide)-grafted multiwall carbon nanotubes (PEO- graft -MWCNT) were successfully prepared by a ring-opening polymerization of ethylene oxide. Thermogravimetric analysis results indicated that the amount of the grafted PEO polymer was about 40.0 wt%. Rigid polyurethane foams (PUFs) filled with MWCNTs and PEO- graft -MWCNT were also fabricated to investigate the influence of grafted PEO interfacial layer on the foaming process, morphology and mechanical properties of PUF. The results indicated that PEO- graft -MWCNT had a limited impact on the viscosity and viscoelastic properties of polyol. Meanwhile, the addition of PEO- graft -MWCNT was beneficial for decreasing the pore size of PUF. The glass transition temperature and mechanical properties of PEO- graft -MWCNT/PUF composites increase gradually with filler content, which can be attributed to the good compatibility and strong interaction between PEO- graft -MWCNT and PUF. © 2018 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2018
·Vol. 67
·期 11
·1535-1544
·
IF 2.352
Huang Tan,Hanqing Wang,Yue Tang,Shuyang Zhang,Wei Yang,Zhengying Liu,Mingbo Yang
A rather low crystallization rate has greatly limited the application of poly( l -lactide) (PLLA) in many fields. Thus, functionalized cellulose nanoparticles (CPNs) were prepared based on cellulose aerogel through a novel and simple approach and were then applied as biobased nucleating agents to improve the crystallization rate of PLLA. First, isolated individual CPNs with a mean diameter around 37.2 nm and regular circular shape were obtained. Subsequently, PLLA based nanocomposites with various contents of CPNs were prepared by solution blending. As a result, CPNs promoted the crystallization rate of PLLA significantly. Compared with that of neat PLLA, the crystallinity ( X c ) of the nanocomposites increased dramatically more than 30 times to 36.65% at a CPN loading of 0.5 wt%, and the half-crystal time ( t 1/2 ) at 130 °C decreased by about 91%. Furthermore, due to the presence of CPNs, which provided a large number of nucleation sites in the PLLA matrix, the chain conformational and crystallization kinetics behavior of the PLLA based nanocomposites during isothermal crystallization were changed in the early stages, and based on this result a proposal for the nucleation process for CPNs in a PLLA matrix is presented. © 2018 Society of Chemical Industry
研究领域:
高分子科学
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纳米材料
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生物聚合物
·
结晶动力学
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2013
·Vol. 63
·期 3
·537-545
·
IF 2.125
Yewei Xu,Xiangwang Cui,Fanghua Zhu,Xuan Luo,Qiang Yin,Lin Zhang
Six new bis(benzimidazolyl) monomers containing ether, sulfonyl and ketone groups were synthesized efficiently. A series of poly( N -arylenebenzimidazole)s were prepared using an aromatic nucleophilic displacement reaction that removed the N–H sites from the novel bis(benzimidazolyl) derivatives with activated aromatic difluorides in sulfolane. The reaction was carried out at 210 °C in the presence of anhydrous potassium carbonate. All resulting polymers showed essentially amorphous patterns. This was consistent with the calculated results. Differential scanning calorimetry and thermogravimetric measurements showed that the polymers had high glass transition temperatures (>240 °C), good thermostability and high decomposition temperatures (>400 °C). These novel polymers also showed easy solubility. © 2013 Society of Chemical Industry
研究领域:
高分子化学
·
材料科学
·
有机合成
·
热分析
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2012
·Vol. 62
·期 2
·219-227
·
IF 1.902
Zhenming Chen,Yan Liu,Chenguang Yao,Guisheng Yang
Double crystalline poly(trimethylene terephthalate)/poly(ethylene oxide terephthalate) copolymers (PTT/PEOT), with PTT content ranging from 16.5 to 65.5 wt%, were synthesized by melt copolycondensation. The morphological transformation of samples from microphase separation to macrophase separation was investigated by gel permeation chromatography and transmission electron microscopy. Differential scanning calorimetry and in situ wide-angle X-ray diffraction suggested that all copolycondensation samples displayed double crystalline behavior. The melt-crystallization peak temperatures ( T m, c values) of PTT chains monotonously increased with increasing PTT content and were higher than that of homo-PTT when the content of PTT was above 30.6 wt%. Interestingly, T m, c values of PEOT chains were also increased with increasing PTT content. Polarized optical microscopy revealed that all copolycondensation samples studied could form ring-banded spherulites and band spacing increased with increasing T c values. In addition, band spacing decreased with increasing PTT content at a given T c . Strangely, although PEOT was the main component in all copolycondensation samples, spherulitic morphology formed by the advance crystallization of PTT did not change after PEOT crystallization. Only a subtle change of quadrant tones was detected. © 2012 Society of Chemical Industry
研究领域:
高分子科学
·
材料化学
·
大分子化学
·
热分析
·
聚合物结晶
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2014
·Vol. 63
·期 12
·2030-2041
·
IF 2.247
Xiaojing Zhang,Chong Li,Yuelei Hu,Ruixue Liu,Linghao He,Shaoming Fang
Octavinyl polyhedral oligomeric silsesquioxane (OVPS) is used as the crosslinker instead of N , N ′-methylenebisacrylamide (BIS) to copolymerize with 2-(dimethylamino)ethyl methacrylate (DMAEMA) or DMAEMA and N -isopropylacrylamide (NIPAM) to prepare hybrid hydrogels: P(OVPS- co -DMAEMA) and P(OVPS- co -DMAEMA- co -NIPAM). The prepared hydrogels are transparent and show dual response to temperature and pH. The hydrogels were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis and tensile tests. Their mechanical properties, swelling ratio, deswelling and reswelling behaviors as well as drug release properties were investigated. The results indicate that OVPS can be incorporated into polymer networks in proportion to feed ratios. The P(OVPS- co -DMAEMA) hydrogel exhibits more homogeneous interior structure, higher swelling ratio and faster response than the conventional hydrogel prepared with BIS. Moreover, the incorporation of OVPS enhances the compression and tensile properties of the hydrogels. The feed ratios of OVPS and NIPAM have a great effect on volume phase transition temperature, thermal sensitivity, swelling behavior, mechanical properties and drug release properties of the hybrid hydrogels. The prepared dual-responsive OVPS-containing hydrogels are expected to be used as biomedical materials in drug release and tissue engineering. © 2014 Society of Chemical Industry
研究领域:
高分子科学
·
生物材料
·
药物递送
·
水凝胶技术
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刺激响应材料
·
组织工程
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2016
·Vol. 65
·期 10
·1187-1194
·
IF 2.414
Meng Ma,Haiming Zheng,Si Chen,Bozhen Wu,Huiwen He,Liqing Chen,Xu Wang
Super-toughened poly( l -lactic acid) (PLLA) was prepared by reactive blending of PLLA with poly(ϵ-caprolactone) (PCL), glycerol and 4,4′-methylenediphenyl diisocyanate. The reactive interfacial compatibility between PLLA and the formed crosslinked polyurethane (CPU) in the PLLA matrix was studied in detail. The morphology and the toughness of the blends can be tuned by changing the CPU content. The results indicate that the impact strength of PLLA shows a tendency to higher values with the increasing PCL content up to 20 wt%. The notched impact strength of the blend with 20 wt% PCL increases to 55.01 kJ m −2 , which is 24.9 times higher than that of neat PLLA. The elongation at break is also increased from 5% to 139.4%, indicating the brittle − ductile transition. The increased interfacial binding strength through the reactive interfacial compatibility and the formation of a CPU network in the PLLA matrix account for the improved toughness of PLLA/CPU blends. Dynamic mechanical analysis results indicate that the compatibility between PLLA and CPU is improved with increasing CPU content resulting in the formation of more interfacial phase. In addition, rheological property measurements indicate that the improvement in storage modulus and complex viscosity is ascribed to the formation of a CPU network in the PLLA matrix. © 2016 Society of Chemical Industry
研究领域:
高分子科学
·
材料工程
·
复合材料
·
塑料与聚合物
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2018
·Vol. 67
·期 8
·1054-1061
·
IF 2.352
Wei Yang,Peiting Pan,Haibo Wang,Xu Cheng,Zongliang Du
Waterborne fluorinated polyurethanes (WFPUs) based on hydroxyl-terminated poly(fluoroalkyl methacrylate)s (HTPFMAs) with different main-chain lengths were synthesized. The structure of HTPFMA was characterized using 1 H NMR spectroscopy, measurements of hydroxyl values and gel permeation chromatography. The microstructures of WFPUs were investigated using Fourier transform infrared spectroscopy, which indicated that hydrogen bonding interactions in hard segments of WFPUs were enhanced by the introduction of HTPFMA and increased with increasing main-chain length of HTPFMA. The results of X-ray diffraction demonstrated that increasing the main-chain length of HTPFMA resulted in an increase of crystallinity in hard segments. Differential scanning calorimetry revealed that the melting temperature of micro-crystallites in hard segments and the microphase separation increased with an increase of HTPFMA main-chain length. Dynamic mechanical analysis and scanning electron microscopy also confirmed that HTPFMA with longer main-chain length can promote the extent of microphase separation of WFPUs between soft and hard domains. The mechanical properties of WFPUs were improved due to the increase of microphase separation with increasing HTPFMA main-chain length. © 2018 Society of Chemical Industry
研究领域:
高分子科学
·
材料化学
·
涂料与表面技术
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DOI
高影响因子
POLYMER INTERNATIONAL
·
2021
·Vol. 70
·期 9
·1344-1355
·
IF 2.99
Zhi-Yuan Zhang,Li-Li Rui,Ya-Li Lin,Hui-Dan Zhang,Ji-Ming Ou,Jian-Feng He,Quan-Zhou Wu
Three-dimensionally ordered macroporous molecularly imprinted polymers (3DOM MIPs) were prepared for the direct purification of cinchona alkaloids from crude cinchona extract. The 3DOM MIPs were easily prepared by grafting quinine-MIPs on the pore walls of 3DOM thiol-group-functionalized silica. The materials were characterized using various techniques. The results showed that the 3DOM MIPs had a more regular macroporous structure, a greater surface area and a greater porosity than traditional bulk MIPs (TBMIPs). The 3DOM MIPs could reach a high MIP content of 69.9%. And the 3DOM structure could improve intraparticle adsorption and provide more accessible adsorption sites. Consequently, in both static adsorption experiments and solid-phase extraction (SPE), the actual adsorption capacity of the imprinted polymers of the 3DOM MIPs was about 83% higher than that of TBMIPs. Moreover, the 3DOM MIPs exhibited high affinity for quinine, quinidine and cinchonine. Using the quinine-3DOM MIPs as SPE sorbent, quinine, quinidine and cinchonine could be effectively purified from crude cinchona extract with high elution recoveries. Control experiments also showed that the 3DOM MIPs were superior to commercially available adsorbents in terms of the purification of cinchona alkaloids from crude extract. © 2021 Society of Chemical Industry
研究领域:
材料科学
·
药物化学
·
分析化学
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DOI
高影响因子
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