2746-19-2Relevant articles and documents
Electro-optic properties of a side chain poly(norbornene-dicarboximide) system with an appended phenyl vinylene thiophene chromophore
Spring, Andrew M.,Qiu, Feng,Hong, Jianxun,Bannaron, Alisa,Yokoyama, Shiyoshi
, p. 13 - 27 (2017)
A side chain EO copolymer series has been synthesized by ROMP using the Grubbs 3rd generation initiator and quenched with ethyl vinyl ether. The copolymers were prepared by combining two norbornene-dicarboximide monomers, one with a cyclohexyl substituent and another substituted with an FTC chromophore. The mol% of the chromophore-substituted monomer was varied from 0.00?mol% to 22.92?mol%, all polymers were obtained in a yield of between 83 and 92% and a purity of between 97 and 98%. The cis:trans vinylene ratio remained constant at 1:1, confirming the polymers were amorphous. Peak molecular weights increased from 29,541?g/mol to 142,113?g/mol and the PDI increased from 1.36 to 4.01 respectively. Glass transition and thermal decomposition temperatures decreased from 206?°C to 168?°C and 433?°C to 382?°C as the mol% of the chromophore-substituted monomer was increased. UV–vis absorbance spectroscopy was used to quantify the chromophore content. A close correlation (68–95%) between the measured and calculated absorbance was found. The polymer containing 22.92?mol% of the chromophore-substituted monomer had a maximum r33 of 70?pm/V when polled at an optimum field of 60?V/μm at a polling temperature of 200?°C. This equates to a high polling efficiency of 1.16. High current flow in this polymer film at elevated field strength caused a breakdown of the electrode, preventing access to an elevated electro-optic coefficient. This polymer was found to have an excellent stability of 76% when aged at 85?°C for 1000?h in air.
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Pirsch
, (1956)
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Preparation method of exo-Dickson anhydride
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Paragraph 0017-0018; 0042-0043; 0046-0049, (2021/10/16)
The preparation method comprises the following steps: (1) adding a solvent in a reaction container, maleic anhydride, a chiral catalyst D and nitrogen to replace air in a reaction container. (2) At -5 - 5 °C, cyclopentadiene is added dropwise, and the dropping is carried out at a certain temperature. (3) After the completion of the reaction, water was added and quenched. Concentration, crystallization in ethanol and filtration gave exo. The preparation method has the characteristics of high reaction stereoselectivity, high yield, good product quality, simple and convenient process operation, high stability and high safety, and is suitable for industrial mass production.
Catalytic Living Ring Opening Metathesis Polymerisation: The Importance of Ring Strain in Chain Transfer Agents
Liu, Peng,Yasir, Mohammad,Kilbinger, Andreas F. M.
supporting information, p. 15278 - 15282 (2019/09/17)
A recently developed catalytic living ring opening metathesis polymerisation (ROMP) was investigated using a series of reversible chain transfer agents (CTA) carrying either cyclopentene or cyclohexene rings, differing only in ring strain. All cyclopentene derivatives examined showed significantly faster reaction rates than the corresponding cyclohexene derivatives. This resulted in lower molecular weight dispersities and better control of the molecular weight for the cyclopentene compared to the cyclohexene CTAs. Both Grubbs’ second and third generation catalysts could be employed in catalytic living ROMP using cyclopentene CTA derivatives. The kinetics of different CTAs were studied, block copolymers were synthesised and residual ruthenium quantified by ICP-OES. All polymers were fully characterised by NMR, GPC and MALDI-ToF mass spectrometry. The new cyclopentene CTAs are readily synthesised in a few straightforward steps and provide faster reaction kinetics than all previously reported reversible CTAs.
