scholarly journals Visible light induced controlled cationic polymerization by in situ generated catalyst from manganese carbonyl

2019 ◽  
Vol 55 (49) ◽  
pp. 7045-7048 ◽  
Author(s):  
Jiajia Li ◽  
Mengmeng Zhang ◽  
Xiangqiang Pan ◽  
Zhengbiao Zhang ◽  
Sébastien Perrier ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Cationic Polymerization ◽  
Irradiation Time ◽  
Light Radiation ◽  
Vinyl Ethers ◽  
Mild Conditions ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Manganese Carbonyl

Controlled cationic polymerization of various vinyl ethers is achieved under light radiation, utilizing commercially available reagents, under mild conditions and the molecular weight distributions can be modulated by simply regulating the irradiation time.

scholarly journals Naturally-Derived Amphiphilic Polystyrenes Prepared by Aqueous Controlled/Living Cationic Polymerization and Copolymerization of Vinylguaiacol with R–OH/BF3·OEt2

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1404 ◽  
Author(s):  
Hisaaki Takeshima ◽  
Kotaro Satoh ◽  
Masami Kamigaito
Keyword(s):  
Molecular Weight ◽  
Ferulic Acid ◽  
Cationic Polymerization ◽  
Living Polymerization ◽  
Block Copolymerization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Living Cationic Polymerization ◽  
Naturally Occurring ◽  
Weight Distributions

In this study, we investigated direct-controlled/living cationic polymerization and copolymerization of 4-vinylguaiacol (4VG), i.e., 4-hydroxy-3-methoxystyrene, which can be derived from naturally-occurring ferulic acid, to develop novel bio-based amphiphilic polystyrenes with phenol functions. The controlled/living cationic polymerization of 4VG was achieved using the R–OH/BF3·OEt2 initiating system, which is effective for the controlled/living polymerization of petroleum-derived 4-vinylphenol in the presence of a large amount of water via reversible activation of terminal C–OH bond catalyzed by BF3·OEt2, to result in the polymers with controlled molecular weights and narrow molecular weight distributions. The random or block copolymerization of 4VG was also examined using p-methoxystyrene (pMOS) as a comonomer with an aqueous initiating system to tune the amphiphilic nature of the 4VG-derived phenolic polymers. The obtained polymer can be expected not only to be used as a novel styrenic bio-based polymer but also as a material with amphiphilic nature for some applications.

A convergent approach to ring polymers with narrow molecular weight distributions through post dilution in ring expansion cationic polymerization

2016 ◽  
Vol 7 (45) ◽  
pp. 6911-6917 ◽  
Author(s):  
Hajime Kammiyada ◽  
Makoto Ouchi ◽  
Mitsuo Sawamoto
Keyword(s):  
Molecular Weight ◽  
Vinyl Ether ◽  
Cationic Polymerization ◽  
Ring Expansion ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Fused Ring ◽  
Ring Polymers ◽  
Convergent Approach

In this paper, we demonstrate a convergent approach to convert “fused” ring chains obtained via ring expansion cationic polymerization of vinyl ether with a hemiacetal ester (HAE)-based ring initiator (1) into “sing” ring ones of narrow MWDs.

Effect of Molecular Weight Distribution of Mineral Oil on Tribofailure of Spur Gears

1981 ◽  
Vol 103 (1) ◽  
pp. 210-218 ◽  
Author(s):  
F. Hirano ◽  
K. Ichimaru ◽  
K. Kinoshita ◽  
T. Sakai
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Film Formation ◽  
Spur Gears ◽  
Mineral Oils ◽  
Mild Conditions ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Failure Loads

Using a series of straight mineral oils with a variety of molecular weight distributions failure loads of spur gears with gear ratios 27:25 and 1:1 were investigated. The failure loads in the case of the synchronous engagement 1:1 were considerably higher than those in the asynchronous engagement 27:25 as a result of imprinting of asperities of harder teeth on softer engaged teeth. The correlation among the results was found to be quite regular, showing the beneficial effect of wide-ranged oils in the molecular weight distribution. Summarizing the obtained results, it is concluded that the failure loads of narrow-ranged oils were conditioned by their viscosity grades, and that those of wide-ranged oils increased further with the aid of oxide film formation on teeth. Results of four-ball tests and two-disk tests previously carried out under mild conditions using the same narrow-ranged and wide-ranged oils show the similar feature to those of the gear tests.

In Situ Synthesis of Polystyrene/SiO2 Hybrid Composites via a 'Grafting Through' Strategy Based on Nitroxide-mediated Radical Polymerisation

2008 ◽  
Vol 16 (9) ◽  
pp. 621-626 ◽  
Author(s):  
Yunpu Wang ◽  
Yongqian Shen ◽  
Xiaowei Pei ◽  
Wenjuan Zhang ◽  
Yuli Wei ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hybrid Composites ◽  
Hybrid Particles ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Radical Polymerisation ◽  
Soft Shell ◽  
Grafting Through ◽  
Vinyl Group

Polymer-grafted nanosilica hybrid composites that possess a hard backbone of nanosilica and a soft shell of brush-like polystyrene (PSt) were prepared via a ‘grafting through’ strategy based on nitroxide-mediated radical polymerisation (NMRP) using 2,2,6,6-tetramethylpiperidine-iV-oxyl (TEMPO) as the mediator. Two steps were used to graft PSt chains to the surface of nanosilica: anchoring of vinyltrimethoxysilane onto the surface of nanosilica, and then using TEMPO to trap the radicals produced by the reaction of benzoyl peroxide (BPO) with styrene and the vinyl group in grafted vinyltrimethoxysilane molecules. Finally, well-controlled molecular weight (Mn) and narrow molecular weight distributions (Mw/Mn) of PSt chains were grown from the surface of nanosilica. The prepared PSt-g–SiO2 hybrid particles have been extensively characterised by FTIR, XPS, TGA, and TEM.

Discrete copper(ii)-formate complexes as catalytic precursors for photo-induced reversible deactivation polymerization

2016 ◽  
Vol 7 (1) ◽  
pp. 191-197 ◽  
Author(s):  
Vasiliki Nikolaou ◽  
Athina Anastasaki ◽  
Francesca Brandford-Adams ◽  
Richard Whitfield ◽  
Glen R. Jones ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Metal Salt ◽  
Good Control ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Reversible Deactivation

Traditional copper-mediated reversible deactivation polymerization techniques (RDRP) employ various components mixedin situ(e.g.ligand, metal salt, additional deactivation speciesetc.) in order to achieve good control over the molecular weight distributions.

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