Derivatives of Synthetic Rubber

Abstract By processes of cyclization and chlorination, synthetic elastomers can be converted into derivatives which differ from the parent product in the following respects: 1. Higher specific gravity. 2. Higher softening point. 3. Greater hardness and rigidity. 4. Less flexibility and elongation. 5. Greater chemical resistance. 6. Lower solution-viscosity. 7. Lower moisture-vapor transfer. 8. Lower moisture absorption. 9. Less tackiness. 10. Greater solubility in polar solvents. Thus, many of the desirable features of the commercially important derivatives of natural rubber can be duplicated in synthetic products. It is, furthermore, logical to assume that the field of usefulness of synthetic derivatives will be extended by selection of the proper type of synthetic rubber for cyclization, chlorination, and hydrochlorination to bring out certain desirable characteristics which are not inherent in products made from natural rubber.

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Qualitative Spot Tests for Rubber Polymers

Rubber Chemistry and Technology ◽

10.5254/1.3543233 ◽

1946 ◽

Vol 19 (3) ◽

pp. 832-843 ◽

Cited By ~ 2

Author(s):

H. P. Burchfield

Keyword(s):

Natural Rubber ◽

Filter Paper ◽

Raw Material ◽

Color Changes ◽

Synthetic Rubber ◽

Large Numbers ◽

Confirmatory Tests ◽

Commercially Important ◽

Spot Tests ◽

Representative Samples

Abstract To eliminate processing difficulties and ensure the production of standard natural and synthetic rubber reclaims, the scrap used as the raw material must be carefully segregated. When mold markings are lost, or large consignments of miscellaneous scrap are received, methods for distinguishing between the basic polymers are necessary. This paper describes a new color reaction which will serve to characterize natural rubber, GR-S, and Perbunan. Confirmatory tests included in the same operation distinguish between the remaining commercially important types. The procedure is sufficiently rapid to be practical in the testing of representative samples from carload shipments, or for establishing the identity of materials on which indecisive results are obtained by less specific methods. For the routine assortment of scrap, spot tests are proposed, which are carried out by holding impregnated filter paper strips in the smoke emitted when the sample is branded with a metal rod heated to redness. Color changes take place which indicate the nature of the polymer. One test distinguishes between natural rubber and GR-S ; a second is specific for Butyl ; a third differentiates Neoprene-GN, Neoprene-ILS, and Perbunan from one another and from the hydrocarbon rubbers. The spot reactions can be carried out very rapidly, and are particularly useful when large numbers of samples must be examined.

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Synthetic derivatives of pulchrol: An antiparasitic natural product

Planta Medica ◽

10.1055/s-0036-1596772 ◽

2016 ◽

Vol 81 (S 01) ◽

pp. S1-S381

Author(s):

P Terrazas ◽

O Sterner

Keyword(s):

Natural Product ◽

Synthetic Derivatives ◽

Derivatives Of

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Synthesis, Cytotoxicity and Antioxidant Activity of New Analogs of RC-121 Synthetic Derivatives of Somatostatin

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520618666180417164344 ◽

2019 ◽

Vol 18 (10) ◽

pp. 1417-1424 ◽

Cited By ~ 2

Author(s):

Emilia Naydenova ◽

Diana Wesselinova ◽

Svetlana Staykova ◽

Ivan Goshev ◽

Ljubomir Vezenkov

Keyword(s):

Antioxidant Activity ◽

Antioxidant Capacity ◽

Cell Line ◽

Cancer Cell ◽

Cancer Cell Line ◽

Colorectal Cancer Cell Line ◽

Cervical Cancer Cell Line ◽

Synthetic Derivatives ◽

Derivatives Of

Background: Based on the structure of RC-121 (D-Phe-c (Cys-Tyr-D-Trp-Lys-Val-Cys)-Thr-NH2, - synthetic derivatives of somatostatin), some analogs were synthesized and tested for in vitro cytotoxic and antioxidant activity. Objectives: The new analogs were modifyed at position 5 with Dap (diaminopropanoic acid), Dab (diaminobutanoic acid) and Orn and at position 6 with the unnatural amino acids Tle (t-leucine). Methods: The in vitro cytotoxic effects of the substances were investigated against a panel of human tumor cell lines HT-29 (Human Colorectal Cancer Cell Line), MDA-MB-23 (Human Breast Cancer Cell Line), Hep G-2 (Human Hepatocellular Carcinoma Cell Line) and HeLa (cervical cancer cell line). The antioxidant capacities were tested by ORAC (Oxygen Radical Antioxidant Capacity) and HORAC (Hydroxyl Radical Averting Capacity) methods. Results: All substances expressed significantly higher antioxidant capacity by comparison with galic acid and Trolox. All substances showed considerable antioxidant capacity as well. Compound 2T (D-Phe-c(Cys-Tyr-DTrp- Dap-Tle-Cys)-Thr-NH2)had the highest antioxidant effect. The compound 4T (D-Phe-c(Cys-Tyr-D-Trp- Orn-Tle-Cys)-Thr-NH2) displayed antiproliferative effect on HeLa cells with IC50 30 µM. The peptide analog 3T (D-Phe-c(Cys-Tyr-D-Trp-Lys-Tle-Cys)-Thr-NH2) exerted the most pronounced inhibition on the cell vitality up to 53%, 56% and 65% resp. against MDA-MB-23, Hep G-2, HeLa in the higher tested concentration. Conclusion: The somatostatin analogs showed moderate influence on the vitality of different tumor cells and could be used in changing their pathology.

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Mastication of Rubber. II. Interpolymerization of Natural Rubber and Neoprene on Cold Milling

Rubber Chemistry and Technology ◽

10.5254/1.3542540 ◽

1956 ◽

Vol 29 (2) ◽

pp. 427-437

Author(s):

D. J. Angier ◽

W. F. Watson

Keyword(s):

Free Radicals ◽

Natural Rubber ◽

Small Molecules ◽

The Other ◽

Polymer Molecules ◽

Commercially Important ◽

The Individual ◽

Cold Mill ◽

General Method ◽

Butadiene Styrene

Abstract The softening of elastomers on cold milling results from scission of the polymer molecules by the applied shearing forces. The ruptured chains are free radicals, which can undergo mutual combination, interaction with oxygen and various additives, and branching (grafting) on to other polymer molecules. A general method of producing graft and block interpolymers between elstomers is therefore indicated, namely, to cold-mill the polymers together in the absence of small molecules which can terminate the polymeric radicals in order that the radicals may cross-terminate or graft onto the polymer molecules of the other type. A survey of several pairs of the commercially important elastomers, natural rubber, butadiene-styrene, Neoprene, and butadiene-acrylonitrile, has shown that cold milling does effect interlinking. Detailed results for the rubber-Neoprene system are reported in this communication. Experimental verification of polymer interlinking was obtained from the solubility properties of the milled elastomers. Cold milling of Neoprene under nitrogen produces gel, whereas of natural rubber does not, but the milling of mixtures gives gels containing natural rubber. Also, the solubilities and precipitation of the milled mixtures cannot be accounted for by these properties of the individual polymers. Finally, Neoprene-natural rubber mixtures, after and not before cold-milling, can be cross-linked by magnesium oxide, with rubber bound into the vulcanizate.

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Development of Coolsmart Functional Knitted Fabrics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.503-504.498 ◽

2012 ◽

Vol 503-504 ◽

pp. 498-502 ◽

Cited By ~ 1

Author(s):

Lan Qing Feng ◽

Yan Jun Liu

Keyword(s):

Pattern Formation ◽

Moisture Absorption ◽

Raw Materials ◽

Knitted Fabric ◽

Machine Code ◽

Knitted Fabrics ◽

Bacterial Function ◽

Fabric Structures ◽

Selection Of

Based on the main features of coolsmart fiber and the theory of knitted fabric structures， two structures of sports and leisure knitted fabrics with fast moisture absorption, description and anti-bacterial function are introduced in this article, detailing the selection of raw materials, pattern formation effect, the machine code organization and cam set out.

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A synthesis of alkylated 3-aminoisoquinolines and related compounds

Australian Journal of Chemistry ◽

10.1071/ch9821391 ◽

1982 ◽

Vol 35 (7) ◽

pp. 1391 ◽

Cited By ~ 4

Author(s):

AJ Liepa

Keyword(s):

Phosphoryl Chloride ◽

Tertiary Amides ◽

Derivatives Of ◽

Related Compounds ◽

Selection Of

N,N-Dialkyl derivatives of 3-aminoisoquinoline have been prepared by reaction of nitriles with various arylacetic acid tertiary amides in the presence of phosphoryl chloride. The synthesis has been extended to include a benzoisoquinoline and annulated isoquinolines by the selection of appropriate amide and nitrile precursors.

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KINETIC MODEL FOR THERMAL DEHYDROCHLORINATION OF CHLORINATED NATURAL RUBBER WITH DIFFERENT CHLORINE CONTENT

Rubber Chemistry and Technology ◽

10.5254/rct.13.86940 ◽

2014 ◽

Vol 87 (2) ◽

pp. 370-382

Author(s):

Jing Chen ◽

Lanzhen He ◽

Yasheng Chen ◽

Jieping Zhong ◽

Canzhong He ◽

...

Keyword(s):

Natural Rubber ◽

Oxidative Degradation ◽

Storage Conditions ◽

Chlorine Content ◽

Heating Process ◽

Lower Temperature ◽

Novel Model ◽

Derivative Thermogravimetry ◽

Selection Of ◽

Thermo Oxidative Degradation

ABSTRACT A novel model for calculating dehydrochlorination kinetics at a lower temperature of chlorinated natural rubber (CNR) is presented. It has been observed that dehydrochlorination is complex and involves three different stages. A model that accounts for dehydrochlorination at lower temperature is proposed. The kinetic parameters are obtained from dehydrochlorination experiments at 60–90 °C. The results of the kinetic calculation show that the apparent activation energy decreases with an increment of chlorine content. Higher chlorine content CNR makes it easier to remove hydrochloric acid when heated, but its dehydrochlorination rate affected by temperature is significantly less than that of the sample with a lower chlorine content. The thermogravimetric/derivative thermogravimetry results show that the beginning temperature of thermo-oxidative degradation rises with the increment of chlorine content. During the heating process, the higher chlorine content CNR is more stable than the lower one. The results suggest the storage conditions and basis for selection of appropriate temperature for the preparation of CNR from latex.

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Phase Morphology, Thermal and Mechanical Properties of Compatibilized Nylon12/Natural Rubber Blends Using PS/MNR

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.844.53 ◽

2013 ◽

Vol 844 ◽

pp. 53-56

Author(s):

Saravalee Saengthaveep ◽

Sadhan C. Jana ◽

Rathanawan Magaraphan

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

Moisture Absorption ◽

Rubber Particle ◽

Impact Resistance ◽

Phase Morphology ◽

Thermal And Mechanical Properties ◽

Binary Blend ◽

Polyamide 12 ◽

The Impact

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.

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