Journal . t. cure. sq. mm. lengtli = 100.) Hrs. min. (a). (b). axb. Smoked 27 Ser. 2 30 1-40 1041 1457 sheet 1 A. Plain 27 Ser. 2 15 1-4 1046 1464 crepe IC. 2 302 45 1-401-5 990972 13941438 Plain 27 Ser. 2 00 1-59 1021 1613 sheet 1 B. In the case of the plain crepe results we have «ldifficulty ui deciding which time shall be consideredthe optimum. This is a rubber which givesexcellent results at all times between 2i and 3hours. It is quite dear, however, from thecurves—Diagram 4b—that the unsmoked sheetcures more rapidly than either the crepe or thesmoked sheet, and even from the figures alone
Journal . t. cure. sq. mm. lengtli = 100.) Hrs. min. (a). (b). axb. Smoked 27 Ser. 2 30 1-40 1041 1457 sheet 1 A. Plain 27 Ser. 2 15 1-4 1046 1464 crepe IC. 2 302 45 1-401-5 990972 13941438 Plain 27 Ser. 2 00 1-59 1021 1613 sheet 1 B. In the case of the plain crepe results we have «ldifficulty ui deciding which time shall be consideredthe optimum. This is a rubber which givesexcellent results at all times between 2i and 3hours. It is quite dear, however, from thecurves—Diagram 4b—that the unsmoked sheetcures more rapidly than either the crepe or thesmoked sheet, and even from the figures alone it is 994 EATON & GRANTHAM—\TrLCANISATION EXPERIMENTS ON PARA RUBBER. [Oct. 13, 1915. seen that it attains its maximum load in a shortertime, vi^. 2 hours as compared %vith 2 J hours inthecase of the smoked slieet and crepe. Also thecollapse in load and extension denoting a markedovercure is reached by the unsmoked sheet at3 hours, whereas this has not been reached bythe smoked sheet and roller. (2) Two sheets of ordinary average thick-ness were prepared from two other sections of thebox, by rolling out on an ordinary sheeting of the slabs from (1) was allowed to air-dryand the other placed in the smoke house, andsimilar treatment was accorded the two rubbers were allowed to remain in the dryinghouse and smoke house re-spectively till the sheetsfrom (2) were drj. The slabs had to becreped subsequently beforevvilcanising; the sheets werealso divided into two, andhalf was mixed direct andhalf creped before mixingso that the following seriesof samples were obtained.(1) Smoked slab creped, (2) air-dried slab creped, (3) smoked sheet, (4) dittocreped when dry, (.5) plainsheet, (6) ditto creped whendry. The vulcanised sampleswere tested and entirelyconfirmed the theory to beenunciated later, which hadbeen indicated by the pre-vious samples of slab andother rapidly vulcanisingrubber. The results givenbelow show the optimumtimes of cure :— Table
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
