/Contents 52 0 R>> endstream � ��� stream /Group <> x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �12Vp�W� <> stream 37 0 obj endobj <> <> <> These allow compounding ingredients to be homogeneously distributed into the rubber. 44 0 obj � ��� x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �14Rp�W� x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �14Qp�W� x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �1Rp�W� 19 0 obj x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �1Sp�W� 28 0 obj The presence of a fundamental sub-unit within this molecular weight range, from which natural rubber of higher molecular weight is built up, is postulated. 47 0 obj 55 0 obj /Contents 6 0 R>> 8 0 obj � ��� <> endobj Basic data on the structure of natural rubber were obtained beginning in the 1870’s by G. Bouchardat, H. Staudinger, and the German scientist C. Harries. endobj <> Crystallization of natural rubber causes the high degree of strength in stretching vulcanized rubbers based on this process. The Soviet scientists A. P. Aleksandrov, V. A. Kargin, and P. P. Kobeko and the American researchers E. Guth, L. R. G. Treloar, and F. T. Wall have investigated the physical properties of natural rubber and developed a theory of its elasticity. � ��� endstream endstream stream endstream 29 0 obj /Contents 58 0 R>> endobj The industrial use of natural rubber became possible after the discovery of the process of vulcanization (C. Goodyear in the United States in 1839 and T. Hancock in Great Britain in 1843). 26 0 obj endobj 5 0 obj <> x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �1Tp�W� <> /Contents 14 0 R>> A. Dogadkin, I. I. Ostromyslenskii, and the American scientist E. H. Farmer. endstream stream endobj x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �1Vp�W� � ��� x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �12Wp�W� endstream endobj �[[���g&Ƣa��%��0���E!W�}��� ��Ǚ���S8|LK�b*Ɗk���q���� ”=(�/P����>"���U��W� ���. x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �1�Pp�W� stream Natural Rubber: Natural rubber is a high molecular weight polymeric material and an elastomer with viscoelastic properties. x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �1Qp�W� <> Natural and sythetic rubber differ in the microstructure; natural rubber consist almost entirely of the cis-1,4 polymer whereas synthetic isoprene is a blend of cis-1,4, trans-1,4 and 3,4 polymer. About Rubber, manufactured; 1 cubic meter of Rubber, manufactured weighs 1 522 kilograms [kg] 1 cubic foot of Rubber, manufactured weighs 95.01536 pounds [lbs] Rubber, manufactured weighs 1.522 gram per cubic centimeter or 1 522 kilogram per cubic meter, i.e. � ��� endstream 11 0 obj <> <> endobj 17 0 obj /Contents 16 0 R>> /Contents 8 0 R>> /Contents 38 0 R>> 58 0 obj Extensive research on the vulcanization of natural rubber was carried out by B. V. Byzov, B. /Contents 42 0 R>> x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �14Wp�W� endobj /Contents 54 0 R>> 10 0 obj � �o� 14 0 obj ]�lkL�����?�`��w�4N��3�1��W��MӅs�m�l�+���&�Y`��l�cu��5��4��r�oާo��iU��y����e�Ѳ��F���H���1V�)+WC�O�xM�&�RHCBnk�T � �f� caoutchouc, crude rubber, a polymer of plant origin, the vulcanization of which produces processed rubber. endobj A production drawback of natural rubber, related to its high molecular weight, is the necessity of mastication before introducing the ingredients of the rubber stock. x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �14Pp�W� stream stream 50 × 106. 7 0 obj endobj 42 0 obj endstream 1 0 obj <> The natural rubber is isolated by coagulation with formic, oxalic, or acetic acid. Typically, the much greater shear from tighter clearances in the lab mixer and tighter mill nips in the lab will lower the molecular weight of any natural rubber causing poorer physical properties than one would expect. The basic types of natural rubber are ribbed smoked sheet (a product of light amber color) and pale crepe (a product of light creamy color; special bleaching agents, such as sodium bisulfite, are added to the latex before isolation and the rubber is not smoked). endstream endobj stream endobj endobj endobj <> endobj x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �14Sp�W� endstream There is also a system of classification for technical standards that regulates the content of impurities in the rubber. stream This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. <> <> endobj � �x� endstream 13 0 obj We use cookies to help provide and enhance our service and tailor content and ads. endobj 35 0 obj stream Natural rubber is one of the elastomers, a group of macromolecular compounds that possess the capacity for considerable reversible deformation at room temperatures and lower. 54 0 obj x�3R��2�35W(�*T0P�R0T(�Y@���@QC= P A�J��� �14Vp�W� stream <> stream Natural rubber is one of the stereoregular polymers; 98-100 percent of the isoprene monomers in its macromolecule are joined in the cis = 1, 4 configuration: The molecular weight of natural rubber is between 1.4 million and 2.6 million, and the content of double bonds in the macromolecule comes to 95-98.5 percent of the theoretical value. endstream According to the International Standard for Quality and Packing (1969), natural rubber is divided into eight international types, including 35 international grades. stream 4 0 obj � �]� Introducing active fillers hardly alters the strength of processed rubbers, but certain other mechanical properties rise substantially (see Table 1). 6 0 obj 32 0 obj endstream <> x��\ݖ�q�����s�9�4 pte�V$��(�qr��5�١��kq�5^]�!r�7���+ $���k��X��!AT�ꫯ~h�Ӎ�I5�V �S�����w�z��Qoo~��鏪���������&��\����&߬U۸ڴ�ES������J[����fOw�F/���1t��W�o���M�P�������~N�~R�>O����4����U�O�Aݝ��~�T|��z���Vӎ�����gc�y���y������y�ax�����0��~�LJ!�Lt>�,�&��1�L�����@���~î~���������;c������]4�T峱�W���o��]�U���oM�mu��HK8�c�7��7�����ȿ���!