POLYMER DEGRADATION AND STABILITY
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2024
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IF 6.3
Tengfei Han,Benzhi Ju,Shufen Zhang
Despite covalent adaptable networks (CANs) imparting the reprocessing performance of crosslinked polymers, due to reversible bond exchange of the dynamic covalent bonds ; it is still a huge challenge to design catalyst-free, fast reprocessing, controlled degradation and raw material recycling biomass base CANs. Here, for the first time, we prepared cellulose CANs base on hemiacetal and acetal bonds (ACCs) via aldehyde and hydroxyl reaction of the dialdehyde crosslinker with hydroxypropyl cellulose (HPC). By regulating the crosslink density and chemical structure of the crosslinked network, ACCs exhibit tunable thermal and mechanical properties. The crosslinked network structure of the ACCs benefits from the rapid bond exchange of the hemiacetal and acetal bonds at elevated temperatures, which allows for rapid stress relaxation and thus, superior reprocessing properties. In addition, it was found that the dynamic exchange of acetals in the ACCs is influenced by the chain length and flexibility of the crosslinker. Moreover, ACCs possess good degradation and cellulose feedstock recycling properties due to the acid sensitivity of the acetal bonds. This work provides an effective solution to the problems of resource waste caused by petroleum-based thermoset plastics.
研究领域:
材料科学
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化学工程
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
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2017
·Vol. 9
·期 12
·698
·
IF 3.364
Yinglei Zhai,Xing Zhou,Lina Jia,Chao Ma,Ronghua Song,Yanhao Deng,Xueyao Hu,Wei Sun
The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive paclitaxel (PTX) prodrug micelles based on functionalized poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) diblock polymer with an acid-cleavable acetal (Ace) linkage (mPEG-PCL-Ace-PTX). The mPEG-PCL-Ace-PTX5with a high drug content of 23.5 wt % was self-assembled in phosphate buffer (pH 7.4, 10 mM) into nanosized micelles with an average diameter of 68.5 nm. The in vitro release studies demonstrated that mPEG-PCL-Ace-PTX5micelles was highly pH-sensitive, in which 16.8%, 32.8%, and 48.2% of parent free PTX was released from mPEG-PCL-Ace-PTX5micelles in 48 h at pH 7.4, 6.0, and 5.0, respectively. Thiazolyl Blue Tetrazolium Bromide (MTT) assays suggested that the pH-sensitive PTX prodrug micelles displayed higher therapeutic efficacy against MCF-7 cells compared with free PTX. Therefore, the PTX prodrug micelles with acetal bond may offer a promising strategy for cancer therapy.Keywords:prodrug;polymer micelles;pH-sensitive;acetal;paclitaxel
研究领域:
药学
·
肿瘤学
✓ 已验证
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
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2022
·
IF 5.204
Juxiang Chen,Ke Zhang,Kuiyuan Zhang,Bo Jiang,Yudong Huang
Phenolic resins with irreversible cross-links structure make them difficult to degrade and recycle. It is an emerging trend for phenolic resins thermoset to develop a rapid and facile closed-loop recycling approach. Herein, the degradable and reprocessable phenolic thermosets (PRTs) based on reversible acetal bonds were synthesized by tri(ethylene glycol) divinyl ether (TEGDVE) and linear phenolic resin through one-step “click” addition reaction. By employing the chain mobility induced by dynamic weak acetal motifs and linear TEGDVE in PRTs, the mechanical strengths could be rationally adjusted, and more moderate reprocessing and degradation conditions were achieved. Accordingly, the flexible structure units containing weak reversible acetal linkages were expected to accelerate the mobility of the chain segments and decrease the reprocessing temperature, while the linear phenolic structure afforded the high mechanical strength. Remarkedly, a champion degradation rate of 121.8 mg·mL −1 ·h −1 was achieved under acid condition by adjusting the ratio of flexible chains consisting of dynamic acetal bonds. In addition, compared with pristine PRTs, regenerative one maintained 93.41% of elongation at break. This work may shed a light for realizing degradable and reprocessable dynamic network materials with high efficiency.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Nianzhao Gao,Yanglei Zheng,Jianan ShangGuan,Haoran Sun,Junyi Jiang,Shuangfei Xiang,Shujun Zhao,Feiya Fu,Xiangdong Liu
The development of sustainable composites necessitates biobased epoxy resins that are highly recyclable and degradable; however, the integration of mechanical, reprocessing, and rapid degradation properties into a single epoxy resin remains a significant challenge. The present study proposes a straightforward approach to overcoming the problem by combining two labile covalent bonds into an epoxy resin. The combination of acetal and disulfide bonds demonstrates a synergistic effect on the degradation performance of epoxy resin, leading to an ultrafast degradation of the epoxy polymer. The carbon fiber-reinforced composite with the epoxy resin matrix shows a tensile strength exceeding 630 MPa, but the epoxy resin degrades completely within just 8 min, while the recovered carbon fibers display nondestructive characteristics similar to those of the original material. Moreover, the epoxy resin that we designed shows good self-healing and reprocessing ability. Scratches on the resin surface can be completely self-healed by heating, while the powdered resin can be reshaped under a hot press. These findings offer a new approach to the preparation of sustainable composites, highlighting the significant importance of the development of thermosetting polymers.
研究领域:
材料科学
·
可持续发展
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Shuai Li,Jiang Zhong,Wenxiong Zhang,Zhenhua Xiong,Fei Gao,Yongluo Qiao,Liang Shen
Conventional polyurethanes from non-renewable resources have been widely used for their excellent mechanical properties and thermal stability, which are difficult to be reprocessed and recycled due to the permanent crosslinked networks. In this study, dynamic acetal bonds were synthesized using bio-based vanillin and then embedded in polymer with castor oil to construct bio-based recyclable polyurethane. The ratio of castor oil to bio-spiroacetal diols was varied to control the thermodynamics and mechanical performance of bio-based polyurethanes. Experimental results of dynamic mechanical analysis, differential scanning calorimetry, tensile test and stress relaxation test suggested that a decrease in the content of acetal diols as a hard segment, led to a decrease in the glass transition temperature and tensile strength. Additionally, the activation energy initially increased and then decreased. The reversibility of the acetal structure endowed green polyurethane materials with the ability of reprocessing, self-repairing and closed-loop recycling.
研究领域:
材料科学
·
高分子化学
·
可持续材料
✓ 已验证
产品关联
DOI
高影响因子
BIOMACROMOLECULES
·
2019
·
IF 5.667
Yuxin Zhang,Jie Zhou,Shengnan Ma,Yiyan He,Jun Yang,Zhongwei Gu
Smart polymers as ideal gene carriers have drawn increasing attentions due to the effective DNA release once triggered by intrinsic stimuli, as well as reduced cytotoxicity. Herein, a stimulus-responsive, positively charged and water-soluble polymer (OEI-TKx) was facilely engineered by cross-linking low molecular weight oligoethylenimine (OEI) via thioketal (TK) linkages that would cleave selectively in reactive oxygen species (ROS)-rich environments induced by hypoxia. Agarose gel electrophoresis assay demonstrated that the threshold N/P ratios for complete retardation of negatively charged DNA migration were above 5 for OEI-TKx. The reduction in DNA-condensing capability and the changes in particle size, size distribution and particle morphology all illustrated that OEI-TKx possessed excellent ROS responsiveness. OEI-TKx/DNA polyplexes showed lower toxicity and higher gene transfection efficiency compared with PEI/DNA polyplexes. The optimum formulation, OEI-TKx/DNA polyplexes (N/P = 40), showed a little better performance than PEI/DNA polyplexes in cellular uptake profile. Furthermore, OEI-TKx/DNA polyplexes could escape from endosomes to the cytosol as efficiently as PEI/DNA polyplexes. Confocal images confirmed that OEI-TKx/DNA polyplexes could more effectively release DNA than PEI/DNA polyplexes, mainly owing to the valid cleavage of thioketal linkages induced by characteristic rich-ROS in Hela cells. These results suggested that OEI-TKx could represent an on-demand stimulus-responsive gene delivery platform.
研究领域:
生物医学工程
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药学
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纳米技术
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分子生物学
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癌症治疗
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）