Effect of Elongation on the Proton Magnetic Resonance of Natural Rubber
Abstract Several authors have already reported their studies on natural rubber by the method of proton magnetic resonance. However, since there has been little work on the effect of elongation on proton magnetic resonance absorption, we present our investigation on the proton magnetic resonance absorption of stretched samples of vulcanized natural rubber. For this experiment a large permanent magnet shown in Figure 1 was constructed. The magnetic field strength was 6090 gauss at the center of the gap at 18° C. The magnet had a field inhomogeneity of about 0.01 gauss in a 0.2 cc. sample. The derivatives of the resonance line were recorded at fixed frequency, changing the magnetic field linearly in time with an automatic electronic bias control. Control of the temperature from liquid nitrogen to room temperature was performed by a cryostat similar to that described by Gutowsky.