نتایج جستجو برای: ring opening polymerization

تعداد نتایج: 195988  

Journal: :Polymer Chemistry 2021

A clickable initiator, pentafluoro benzyl bromide, has been investigated for the cationic ring opening polymerization of poly(2-oxazolines).

2017
Jingwei Fan Yannick P. Borguet Lu Su Tan P. Nguyen Hai Wang Xun He Jiong Zou Karen L. Wooley

Well-defined molecular brushes bearing polypeptides as side chains were prepared by a "grafting through" synthetic strategy with two-dimensional control over the brush molecular architectures. By integrating N-carboxyanhydride ring-opening polymerizations (NCA ROPs) and ring-opening metathesis polymerizations (ROMPs), desirable segment lengths of polypeptide side chains and polynorbornene brush...

2009
S. S. Liow L. K. Widjaja V. T. Lipik M. J. M. Abadie

Vinyl functionalized poly (ε-caprolactone) with molar mass ranging from 500–5000 Da were synthesized by ring opening polymerization and further photopolymerized. One-step synthesis and functionalization is achieved based on ring opening polymerization (ROP). Hydroxyl butyl vinyl ether (HBVE) was employed to play the role as the initiator of ROP, and photo-curable functional group. The presence ...

Journal: :ACS macro letters 2013
Yanfeng Zhang Qian Yin Hua Lu Hongwei Xia Yao Lin Jianjun Cheng

Amphiphilic polypeptide-containing hybrid dual brush block copolymers with controlled molecular weights and narrow molecular weight distributions were synthesized in one pot via ring-opening metathesis polymerization of sequentially added norbornyl-PEG and N-(2-((trimethylsilyl)amino)ethyl)-5-norbornene-endo-2,3-dicarboximide (M1) followed by ring-opening polymerization of amino acid N-carboxya...

2012
Hong Cao Haobo Han Guangquan Li Jiebing Yang Lingfei Zhang Yan Yang Xuedong Fang Quanshun Li

The ring-opening polymerization of δ-valerolactone catalyzed by a thermophilic esterase from the archaeon Archaeoglobus fulgidus was successfully conducted in organic solvents. The effects of enzyme concentration, temperature, reaction time and reaction medium on monomer conversion and product molecular weight were systematically evaluated. Through the optimization of reaction conditions, poly(...

Journal: :Dalton Transactions 2021

Rare examples of titanium oxa- and aza-calixarenes are reported which active for the ring opening polymerization (ROP) ?-caprolactone, ?-valerolactone rac-lactide.

2012
Vitali T. Lipik Marc J. M. Abadie

Well-defined di- and triblock copolymers consisting of ε-caprolactone (CL), L-lactide (LA), and trimethylene carbonate (TMC) were synthesized via "PLA first route" in coordinated anionic ring opening polymerization/copolymerization (CAROP) with tin (II) octoate as catalyst. The desired block structure was preserved by use of protective additive α-methylstyrene by preventing the transesterificat...

Journal: :Organometallics 2010
Benjamin K Keitz Robert H Grubbs

Ru-based olefin metathesis catalysts containing carbohydrate-derived NHCs from glucose and galactose were synthesized and characterized by NMR spectroscopy. 2D-NMR spectroscopy revealed the presence of Ru-C (benzylidene) rotamers at RT and the rate of rotation was measured using magnetization transfer and VT-NMR spectroscopy. The catalysts were found to be effective at ring-opening metathesis p...

Journal: :Chemical communications 2012
Cuiling Xu Insun Yu Parisa Mehrkhodavandi

An ethoxy-bridged dinuclear indium catalyst was used for the ring opening polymerization of the cyclic ester β-butyrolactone to form the biodegradable polyester poly(hydroxybutyrate) (PHB). The catalyst shows remarkable activity and control during polymerization, allowing for formation of diblock polymers. Addition of high ratios of alcohols to the catalyst leads to fast chain transfer and immo...

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