ROMP of acetoxy-substituted dicyclopentadiene to a linear polymer with a high Tg

RSC Advances ◽  
2015 ◽  
Vol 5 (33) ◽  
pp. 26185-26188 ◽  
Author(s):  
Laijiang Gong ◽  
Kun Liu ◽  
Encai Ou ◽  
Feng Xu ◽  
Yanbing Lu ◽  
...  
Keyword(s):  

The acetoxy group was introduced to polydicyclopentadiene via ROMP of acetoxy-substituted dicyclopentadiene resulting in a linear polydicyclopentadiene derivative with high Tg.

1984 ◽  
Vol 45 (1) ◽  
pp. 151-155 ◽  
Author(s):  
M. Daoud ◽  
F. Family
Keyword(s):  

1986 ◽  
Vol 51 (4) ◽  
pp. 930-936 ◽  
Author(s):  
Helena Velgová

Alkaline saponification of the 3-acetoxy group in 3,4a-disubstituted 4,4-dimethyl-5,6β-epoxy-A-homo-5βcholestane derivatives I-VI was studied. It was found that the 3α- and 4aα-hydroxy groups participated in the cleavage of the 5β,6β-epoxide ring in the derivatives II-IV: the 5(O)n participation by the 3α-hydroxy group (the derivatives III and IV) led to formation of the transannular 3α,5α-epoxides XII and XIV whereas the participation by the 4aα-hydroxy group (the derivatives II and IV) gave rise to the 4aα,5α-epoxides IX and XV. The 5(O)n participation by the 3α-hydroxy group predominated over the preparation by the 4aα-hydroxy group. In the case of the 4a-keto epoxides V and VI the retroaldol-aldol type isomerization led to formation of 3β-hydroxy-4,4-dimethyl-5,6β-epoxy-A-homo-5β-cholestan-4a-one as the main component of the equilibration mixtures.


2021 ◽  
Author(s):  
Fabian R. Bloesser ◽  
Sarah L. Walden ◽  
Ishrath M. Irshadeen ◽  
Lewis C. Chambers ◽  
Christopher Barner-Kowollik

We demonstrate the light-induced, crosslinker mediated collapse of linear polymer chains into single-chain nanoparticles (SCNPs) capable of self-reporting their unfolding.


Author(s):  
Jie Chen ◽  
Yifei Wang ◽  
Weixing Chen

Multilayer composites have the potential applications in organic film capacitors due to their excellent dielectric and breakdown characteristic. However, poor efficiency (η) and limited available energy density (Ue) of the...


2021 ◽  
Vol 23 (10) ◽  
pp. 5984-5991
Author(s):  
Letizia Tavagnacco ◽  
Ester Chiessi ◽  
Emanuela Zaccarelli

By using extensive all-atom molecular dynamics simulations of an atactic linear polymer chain, we unveil the role of pressure in the coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM).


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2095
Author(s):  
Dae Hoon Lee ◽  
Yoshinori Arisaka ◽  
Asato Tonegawa ◽  
Tae Woong Kang ◽  
Atsushi Tamura ◽  
...  

The cytocompatibility of biological and synthetic materials is an important issue for biomaterials. Gelatin hydrogels are used as biomaterials because of their biodegradability. We have previously reported that the mechanical properties of gelatin hydrogels are improved by cross-linking with polyrotaxanes, a supramolecular compound composed of many cyclic molecules threaded with a linear polymer. In this study, the ability of gelatin hydrogels cross-linked by polyrotaxanes (polyrotaxane–gelatin hydrogels) for cell cultivation was investigated. Because the amount of polyrotaxanes used for gelatin fabrication is very small, the chemical composition was barely altered. The structure and wettability of these hydrogels are also the same as those of conventional hydrogels. Fibroblasts adhered on polyrotaxane–gelatin hydrogels and conventional hydrogels without any reduction or apoptosis of adherent cells. From these results, the polyrotaxane–gelatin hydrogels have the potential to improve the mechanical properties of gelatin without affecting cytocompatibility. Interestingly, when cells were cultured on polyrotaxane–gelatin hydrogels after repeated stress deformation, the cells were spontaneously oriented to the stretching direction. This cellular response was not observed on conventional hydrogels. These results suggest that the use of a polyrotaxane cross-linking agent can not only improve the strength of hydrogels but can also contribute to controlling reorientation of the gelatin.


Author(s):  
Kazuma Muto ◽  
Takaaki Kumagai ◽  
Fumitoshi Kakiuchi ◽  
Takuya Kochi
Keyword(s):  

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