Crosslinking of cellulosics by high energy radiation. II

Leavitt, F.

doi:10.1002/pol.1961.120510121

Cited by 17 publications

(4 citation statements)

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“…Although the radiation-induced polymerization of any carbohydrate would be of interest from a purely scientific viewpoint, glucose was chosen because of the prior work of Barker, et al (1), and because of its relationship to cellulose and the broader problem of crosslinking of cellulosic materials. Several authors (9)(10)(11) have reported the crosslinking of cellulosic materials by radiation, but the chemistry of the process is not understood. Since the crosslinking mechanism in this case is believed to be similar to that of the polymerization of the monomer, it seems logical to first study the simpler case of the polymerization of glucose.…”

Section: Choice Of Sugar and Radiation Sourcementioning

confidence: 99%

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Polymer production from aqueous solutions of D‐glucose by high‐energy radiation

Snell

1965

J. Polym. Sci. A Gen. Pap.

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Recent work by Barker, et al. (1) indicated that a high yield of nondialyzable material (i.e., material retained by a dialysis membrane) could be obtained by -irradiating deaerated aqueous solutions of glucose with gamma-rays from a cobalt-60 source. As a result of several chemical tests conducted on the material, they suggested that the nondialyzable material was a polymer of gluconic acid linked together by carbon-carbon bonds. No indication of the size and shape of the molecules was given.In this thesis, 1.0% aqueous glucose solutions were irradiated with high energy electrons. The yield of polymer, measured as either nondialyzable material or ethanol precipitate, increased with both the dose and the dose rate. This would be expected in view of Barker's proposed mechanism which involves hydrogen abstraction from the sugar molecules followed by coupling of the resulting sugar free radicals.Increasing the dose rate would be expected to increase the concentration of hydrogen and hydroxyl free radicals, which in turn would increase the concentration of sugar free radicals and thus increase the liklihood of radical coupling.The weight average molecular weights of the whole polymers isolated by ethanol precipitation were measured by light scattering in water solution. The molecular weights ranged from 9800 to 5,000,000, and hence are much larger than previously imagined. Measurement of the number average molecular weight of one of the polymers by osmometry established an M/Mn ratio of 4.9, thus indicating a broad distribution of molecular weights within the polymer.The polymers exhibited intrinsic viscosities in the range of 0.02 to 0.26 dl./g. in water at 30.000 + 0.005°C., and are therefore thought to be very highly branched.Although no molecular weights were obtained, the authors assumed the material was polymeric, and devoted most of their work to a chemical characterization of the material. The work on the polymer formed by the 7.10 megarad (Mrad) treatment of glucose is of particular interest to this thesis, and may be summarized as follows:a. The material was acidic, having an equivalent weight of 328, or a carboxyl content of 13.7%.b. The polymer had an aldehyde content of 16.0%, as measured by alkaline hypoiodite.c. The polymer was resistant to acid hydrolysis.In fact, most of the polymer precipitated in hot acid. The precipitate had an infrared absorption spectrum similar to that of the original polymer, and the soluble portion showed no mobile components with paper chromatography.d. The polymer contained 51.91% carbon and 5.07% hydrogen.e. The polymer exhibited absorption at approximately 265 mu in the ultraviolet.f. The polymer reacted with sodium metaperiodate; about one-third of the material remained nondialyzable.From the above information, the authors concluded that the polymeric linkage was neither that of a glycoside nor an ester. Instead, they proposed a carboncarbon linkage similar to that formed upon irradiation of alcohols (2, .3).The proposed mechanism involved the production of H. and .OH ra...

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Section: Choice Of Sugar and Radiation Sourcementioning

confidence: 99%

“…H 0+ e -H 0* + e' (excitation) (9) where e' is a secondary electron and e'-is simply a lower energy state of the s electron e-. This initial step is often referred to as the physical stage, and has a duration of 10- 1 3 sec.…”

Section: Watermentioning

confidence: 99%

Polymer production from aqueous solutions of D‐glucose by high‐energy radiation

Snell

1965

J. Polym. Sci. A Gen. Pap.

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“…A gamma irradiation technique has been used for polymer crosslinking since the gamma irradiation is able to freely control the physical properties by only adjusting the irradiation dose without changing the composition of the material [30]. Crosslinking using gamma irradiation has no necessity to remove the remaining chemical additives after crosslinking since no harmful chemical crosslinking agent or initiator is used, and no need to apply heat during the reaction [31,32,33]. Furthermore, radiation crosslinking can cause a chemical reaction in a solid state or a low-temperature, and energy consumption is less than other methods due to reacting in a short time.…”

Section: Introductionmentioning

confidence: 99%

Effect of Titanium Implants Coated with Radiation-Crosslinked Collagen on Stability and Osseointegration in Rat Tibia

et al. 2018

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This study aimed to evaluate the titanium (Ti) implants coated with collagen type I crosslinked using gamma-irrigation or glutaraldehyde (GA). The in vitro surface observations, quantification assay, and cell studies using human mesenchymal stem cells (hMSCs) were conducted. For in vivo experiments, the implants were divided into three groups and inserted into the rat tibias: control group (non-treated Ti implant), GA group (Ti implants coated with GA-crosslinked collagen) and 25 kGy group (Ti implants coated with gamma-radiation-crosslinked collagen at dose of 25 kGy). The animals were sacrificed at 4 weeks after implantation and the tissue sections were obtained. New bone volume (mm3) and bone-to-implant contact (BIC, %) within the region of interest (ROI) was measured. The in vitro results showed the highest osteogenic differentiation and levels of osteogenesis-related gene expressions in the 25 kGy group without cytotoxicity. The new bone volume of GA group was significantly higher than the control (p < 0.05). In the result of the BIC, the 25 kGy group was significantly higher than the control (p < 0.05). However, there was no significant difference between the experimental groups. Within the limitations of this study, Ti implant coated with gamma-radiation-crosslinked collagen has potential utility without side effects from chemical agents.

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“…In an investigation of the pH of a solution, the glass electrode as well as the reference electrode are generally placed in the solution whose pH is to be measured. In the intragastric determination of pH on patients several investigators have placed the reference electrode on the rectal mucosa, oral mucosa (2,16,17,30), or on the skin (8,15,21,24,25,26) instead of having both electrodes in the stomach (6,7,9,23,24). Below, the technique and accuracy of the skin electrode method will be described.…”

mentioning

confidence: 99%

Continuous Intragastric pH Determination

Kristensen¹

1965

Journal of Internal Medicine

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Crosslinking of cellulosics by high energy radiation. II

Cited by 17 publications

References 0 publications

Polymer production from aqueous solutions of D‐glucose by high‐energy radiation

Polymer production from aqueous solutions of D‐glucose by high‐energy radiation

Effect of Titanium Implants Coated with Radiation-Crosslinked Collagen on Stability and Osseointegration in Rat Tibia

Continuous Intragastric pH Determination

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