Direct evidence of main-chain scissions induced by ultrasonic irradiation of benzene solutions of polymers

Tabata, Masayoshi; Miyazawa, Takashi; Kobayashi, Osamu; Sohma, Junkichi

doi:10.1016/0009-2614(80)85230-4

Cited by 63 publications

(35 citation statements)

References 6 publications

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“…In particular, a remarkable effect of ultrasound on polymers degradation reactions was observed in solution and melt conditions [12][13][14][15]. The breakage of molecular chains under ultrasound occurs near the center of the chain and results in formation of macroradicals, as previously demonstrated by Tabata et al [16]. These macroradicals can further react by transfer processes or by combination, modifying the initial molecular weight distribution.…”

Section: Introductionmentioning

confidence: 86%

Ultrasonic compatibilization of polyelectrolyte complex based on polysaccharides for biomedical applications

Belluzo

Medina

Cortizo

et al. 2016

Ultrasonics Sonochemistry

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a b s t r a c tIn recent years, there has been an increasing interest in the design of biomaterials for cartilage tissue engineering. This type of materials must meet several requirements. In this study, we apply ultrasound to prepare a compatibilized blend of polyelectrolyte complexes (PEC) based on carboxymethyl cellulose (CMC) and chitosan (CHI), in order to improve stability and mechanical properties through the interpolymer macroradicals coupling produced by sonochemical reaction. We study the kinetic of the sonochemical degradation of each component in order to optimize the experimental conditions for PEC compatibilization. Scaffolds obtained applying this methodology and scaffolds without ultrasound processing were prepared and their morphology (by scanning electron microscopy), polyelectrolyte interactions (by FTIR), stability and mechanical properties were analyzed. The swelling kinetics was studied and interpreted based on the structural differences between the two kinds of scaffolds. In addition we evaluate the possible in vitro cytotoxicity of the scaffolds using macrophage cells in culture. Our results demonstrate that the ultrasound is a very efficient methodology to compatibilize PEC, exhibiting improved properties compared with the simple mixture of the two polysaccharides. The test with murine macrophage RAW 264.7 cells showed no evince of cytotoxicity, suggesting that PEC biomaterials obtained under ultrasound conditions could be useful in the cartilage tissue engineering field.

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Section: Introductionmentioning

confidence: 86%

Ultrasonic compatibilization of polyelectrolyte complex based on polysaccharides for biomedical applications

Belluzo

Medina

Cortizo

et al. 2016

Ultrasonics Sonochemistry

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“…22,178 Sohma et al reported that an ESR signal was observed for the sonication of PMMA in benzene in the presence of pentamethyl nitrosobenzene (PMNB), a spin-trap reagent ( Figure 13). 178 No ESR signal was observed for the control experiment without polymer under the same conditions. The macromolecular radicals generated by chain scission of the polymer upon sonication can initiate the polymerization of a second unsaturated monomer.…”

Section: Homolytic Bond Cleavagementioning

confidence: 97%

Mechanically-Induced Chemical Changes in Polymeric Materials

et al. 2009

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Polymeric materials exhibit an extraordinary range of mechanical responses (Figure 1a), which depend on the chemical and physical structure of the polymer chains. 3 Polymers are broadly categorized as thermoplastic, thermoset, or elastomer. Thermoplastic polymers consist of linear or branched chains and can be amorphous or semicrystalline. The mechanical response of thermoplastic polymers is highly influenced by the molecular mass, chain entanglements, chain alignment, and degree of crystallinity. Thermosetting polymers consist of highly cross-linked three-dimensional networks. The mechanical properties of these amorphous polymers depend on the molecular mass and the cross-link density. Elastomers (e.g., rubber) are highly deformable elastic networks that are lightly cross-linked by chemical or physical junctions. Mary M. Caruso (center) was born and raised in Tampa, FL. She received a B.S. degree in Chemistry from Elon University (Elon, NC) in 2006, where she worked under the direction of Prof. Karl D. Sienerth. Her research included the synthesis and electrochemical characterization of a novel palladium complex. She is currently pursuing her Ph.D. in Organic Chemistry at the University of Illinois at Urbana-Champaign under the guidance of Prof. Jeffrey S. Moore and Prof. Scott R. White. Her research interests include the development of new catalyst-free self-healing polymers, microencapsulation, and mechanical testing of bulk polymers. Douglas A. Davis (second from left) was born in Martin, TN. In 2004, he received his B.S. degree in Chemistry from the University of Tennessee, Knoxville, where he worked on surface enhanced Raman spectroscopy (SERS) in an electrospray plume with Professors Charles Feigerle and Kelsey Cook. He joined Prof. Jeffrey Moore's group at the University of Illinois, Urbana-Champaign in 2005 to pursue his Ph.D. in Organic Chemistry. His current research interests include designing and synthesizing mechanophores, which can be induced to undergo chemical reactions with mechanical force. Qilong Shen (third from left) was born in 1974 in Zhejiang Province, China. He received his B.S. degree in Chemistry (1996) from Nanjing University, China, and his M.S. in Chemistry (1999) from Shanghai Institute of Organic Chemistry, the Chinese Science Academy, China, under the supervision of Prof. Long Lu. After a two-year stay at the University of Massachusetts at Dartmouth with Prof. Gerald B. Hammond, he moved to Yale University, where he received his Ph.D. under the guidance of Prof. John F. Hartwig in 2007. He is currently a postdoctoral researcher with Prof. Jeffrey S. Moore at University of Illinois at Urbana-Champaign. His research interests include the discovery, development, and understanding of new transition metal-catalyzed reactions, and the mechanochemistry of polymers.

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“…Electron spin resonance experiments have shown that scission takes place preferentially around the middle of the chain. [14,15] The scission mechanism has been discussed by many authors. [1,2] The viscous forces, shock waves or a combination of the two are commonly quoted as the main agent in chain scission.…”

Section: Introductionmentioning

confidence: 99%

A New Model for the Evolution of the Molecular Weight Distribution of Polymers During Ultrasonic Chain Scission

Giz¹,

Çatalgil‐Giz²,

Sunar³

2001

Macromol. Theory Simul.

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A new model for ultrasonic scission of polymer chains has been developed. The model takes the coiled nature of the polymer chains into consideration. The time evolution of the molecular weight distribution for several values of the solvent quality parameter is obtained using the new model. It is seen that the model leads to higher scission rates and lower final molecular weights for better solvents in accord with the experiments. Simulated gel permeation chromatography results are also in line with the experiments.

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Direct evidence of main-chain scissions induced by ultrasonic irradiation of benzene solutions of polymers

Cited by 63 publications

References 6 publications

Ultrasonic compatibilization of polyelectrolyte complex based on polysaccharides for biomedical applications

Ultrasonic compatibilization of polyelectrolyte complex based on polysaccharides for biomedical applications

Mechanically-Induced Chemical Changes in Polymeric Materials

A New Model for the Evolution of the Molecular Weight Distribution of Polymers During Ultrasonic Chain Scission

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