Recent Studies of the Fine Structure of Carbon Blacks

The paracrystalline nature of the fine structure of carbon blacks was first shown in high resolution phase contrast micrographs by Hess and Ban. These authors described the continuous network of distorted graphite layers within the carbon particles. Measurements of the spacings between these layers has been the subject of our recent work.The results show that the interplanar spacings have a distribution of sizes in all carbon blacks; for example, the variation in interplanar spacings in furnace blacks ranged from approximately 345 pm (picometers) to 450 pm. In addition, the spacing distribution is independent of both the size of the carbon particles or the degree of interparticle fusion.Carbon blacks made by the Oil Furnace Process and the Channel Process have the same fine structure, and the distribution of their spacings follows a log-normal distribution pattern. The average spacing for these carbons is 386 ±6 pm. The value obtained by X-ray diffraction methods, approximately 355 pm, is lower because the data is restricted solely to parallel planes.

Reaction of Free Fatty Acids with Protein in Cod Muscle Frozen and Stored at −29 C after Aging in Ice

Freezing and holding cod muscle in the frozen state favored the association process that involves protein–free fatty acid (FFA) complex formation and begins during aging in ice. Changes in protein extractability, in ultracentrifugal patterns of protein extracted, and in phase contrast micrographs of inextractable muscle fragments were followed in muscle that had been aged in ice to produce various contents of FFA and then frozen and held at −29 C. After 11 months, these changes, which took place largely during the first week of storage, were comparable with those that occur when the FFA are formed during frozen storage. The results were consistent with a reaction rate that was greater at −29 C than at temperatures a few degrees above 0 C.

Structure of Vulcanized and Unvulcanized SBR/BR Blends

Mainly from the temperature dependence of transitions in dynamic modulus, loss tangent, and dielectric loss, associated with microbrownian motions of main chains, it was concluded that blends of NR and BR are microheterogeneous and those of SBR and BR are almost microhomogeneous. Furthermore, even SBR/BR blends tended to be heterogeneous if the styrene content in SBR was increased. On the other hand, unvulcanized SBR/BR blends have been reported to be heterogeneous from observation of phase contrast micrographs. To investigate this vulcanization effect further, measurements of temperature dependence of dynamic modulus and tan δ of unvulcanized blends were compared with those of vulcanized blends.