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Kazuhiko Hashimoto Sirinat Wibullucksanakul Mitsuyasu Matsuura Masahiko Okada 《Journal of polymer science. Part A, Polymer chemistry》1993,31(12):3141-3149
Ring-opening polyaddition of a saccharic acid dilactone prepared from D-glucose, D-glucaro-1,4 : 6,3-dilactone, with several alkylenediamines proceeded at room temperature with no catalyst. The resulting new polyamides carrying many pendant hydroxyl groups, poly(alkylene D-glucaramide)s, were more amorphous and hydrophilic than the corresponding nylons having no hydroxyl groups, and were hydrolyzed more easily than the latter in an acidic condition. The ring-opening ability of D-mannaro-1,4:6,3-dilactone, which was another saccharic acid dilactone obtained from D-mannitol, was found to be lower than that of the D-glucaric analogue. © 1993 John Wiley & Sons, Inc. 相似文献
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Based on the unique absorbent characters and three-dimensional network structure of polyacrylamide (PAM) superabsorbent polymer, a photocatalytic degradable TiO2/PAM composite was synthesized by an aqueous solution polymerization method with N,N′-methylene bisacrylamide as crosslinker, potassium peroxydisulfate as initiator, acrylamide as monomer, and TiO2 (P-25) as functional filler. The photocatalytic degradability of the composite was evaluated using methyl orange as photodegradation target, and the recovery and reproducibility of the composite was investigated. It was found that TiO2/PAM composite had a good photocatalytic degradability, the composite also possessed a good reproducibility of photocatalytic degradability, which is possible to be used in practical process. 相似文献
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Miroslav Vetrík Martin P?ádnýMartin Hrubý Ji?í Michálek 《Polymer Degradation and Stability》2011,96(5):756-759
We describe the synthesis of new crosslinker N′-{3-[2-(4-{2-[3-(methacryloylamino)propanoyl]hydrazono}cyclohexyliden)hydrazino]-3-oxopropyl}-2-methylacrylamide, which is stable at physiological pH, but is hydrolytically cleaved in acidic pH. Study of acid hydrolysis showed that the crosslinker is hydrolyzed into two N′-(3-hydrazino-3-oxopropyl)-2-methylacrylamide molecules and one 1,4-cyclohexanedione molecule. Hydrogels based on poly[N-(2-hydroxypropyl)methacrylamide] crosslinked with this crosslinker were prepared and their degradation rate was studied as a function of pH (in the range of pH 1.5-7.4). The hydrogel is cleaved within 8-27 days at pH between 1.5 and 6 and is stable at pH 7.4 making it promising for the construction of oesophageal stents. 相似文献
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Ring Opening Metathesis Polymerization of Bicyclic α,β‐Unsaturated Anhydrides for Ready‐to‐be‐grafted Polymers Having Tailored pH‐Responsive Degradability 下载免费PDF全文
Heejin Kim Sungwhan Kim Sunyoung Kang Youngjun Song Dr. Suyong Shin Dr. Seonju Lee Minji Kang Dr. So Hee Nam Prof. Dr. Yan Lee 《Angewandte Chemie (International ed. in English)》2018,57(38):12468-12472
Polymers having α,β‐unsaturated anhydrides as repeating units were synthesized by ring opening metathesis polymerization (ROMP). The anhydride moieties were ready‐to‐be‐grafted with amines to form acid‐labile cis‐α,β‐unsaturated acid amide linkages. The pH‐responsive reversible de‐grafting can be controlled by changing the intramolecular accessibility between acid and amide groups. The alendronate‐grafted ROMP polymers showed distinct pH‐dependent cytotoxicity according to the anhydride structures. 相似文献
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Effects of gamma irradiation on chemical composition and ruminal protein degradation of canola meal 总被引:1,自引:0,他引:1
P. Shawrang A. Nikkhah A. Zare-Shahneh A.A. Sadeghi G. Raisali M. Moradi-Shahrebabak 《Radiation Physics and Chemistry》2008,77(7):918-922
Gamma irradiation of canola meal (at doses of 25, 50 and 75 kGy) could alter its ruminal protein degradation characteristics by cross-linking of the polypeptide chains. This processing resulted in decrease (linear effect, P<0.001) of ruminal protein degradation and increase (linear effect, P<0.001) of intestinal protein digestibility. The results showed that gamma irradiation at doses higher than 25 kGy can be used as a cross-linking agent to improve protein properties of supplements in ruminant nutrition. 相似文献
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《Macromolecular bioscience》2018,18(6)
Biodegradable shape memory polymers are promising biomaterials for minimally invasive surgical procedures. Herein, a series of linear biodegradable shape memory poly(ε‐caprolactone) (PCL)‐based polyurethane ureas (PUUs) containing a novel phenylalanine‐derived chain extender is synthesized. The phenylalanine‐derived chain extender, phenylalanine‐hexamethylenediamine‐phenylalanine (PHP), contains two chymotrypsin cleaving sites to enhance the enzymatic degradation of PUUs. The degradation rate, the crystallinity, and mechanical properties of PUUs are tailored by the content of PHP. Meanwhile, semicrystalline PCL is not only hydrolytically degradable but also vital for shape memory. Good shape memory ability under body temperature is achieved for PUUs due to the strong interactions in hard segments for permanent crosslinking and the crystallization‐melt transition of PCL to switch temporary shape. The PUUs would have a great potential in application as implanting stent. 相似文献
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聚己内酯-聚丙交酯-聚醚三元共聚高分子微粒及其降解的研究 总被引:2,自引:0,他引:2
用乳化- 溶剂蒸发法制备了聚己内酯- 聚丙交酯- 聚醚三元无规共聚物微粒,且与用相同方法制备的聚己内酯(PCL) 和聚己内酯- 聚醚嵌段共聚物微粒的形态进行了比较,讨论了材料的亲水性,以及三元无规共聚物中亲水性聚醚链段的长度及含量对所形成微粒形态的影响。研究结果表明,随着聚合物由疏水性向亲水性转变,所生成微粒的形态则从光滑、多孔、到不规则变化。证明了三元无规共聚物多孔微粒的形成是由于亲水的聚醚链段向水相取向所致。在37 ℃、pH7 .4 的缓冲液中进行了三元无规共聚物微粒的降解,结果表明,随着降解时间的延长, 三元无规共聚物的分子量逐渐下降,且其中的聚醚链段含量有明显的降低。 相似文献
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