𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Temperature dependence of proton spin-lattice and spin-spin relaxation times in isotactic polypropylene. Effect of annealing

✍ Scribed by Hiroshi Tanaka; Fumie Kohrogi; Kazuhiko Suzuki

Publisher
Elsevier Science
Year
1989
Tongue
English
Weight
356 KB
Volume
25
Category
Article
ISSN
0014-3057

No coin nor oath required. For personal study only.

✦ Synopsis

The temperature dependences of the proton spin-lattice, Tt, and spin-spin, T2, relaxation times of isotactic polypropylene films with different thermal histories and atactic fraction were investigated. A T~ minimum occurs for both melt-quenched and annealed samples at about 70°C. It shifts to lower temperatures with increasing atactic fraction. T~ at the minimum is longer for the annealed sample than for the melt-quenched. For the sample annealed at high temperatures, two T~ values were observed. Three T 2 values, in increasing order T2c, T2m and T2~, were obtained for all samples. With increasing temperature, T2~ and T2m increase, while T~ remains constant. The fraction of crystalline regions decreases with increasing temperature. The relaxation rate at the T~ minimum, I/T~ minimum, increases linearly with increasing fraction of amorphous regions except for the melt-quenched sample. The viscoelasticity of the sample was also measured. The peak temperature of tan 6 falls as the annealing temperature is raised. T2a for the samples annealed at various temperatures does not correlate linearly with the peak temperature of tan 3.

📜 SIMILAR VOLUMES

Temperature dependence of proton spin-la
Temperature dependence of proton spin-lattice and spin-spin relaxation times of highly stretched isotactic polypropylene film
✍ Hiroshi Tanaka; Kiyohide Takagi 📂 Article 📅 1990 🏛 Elsevier Science 🌐 English ⚖ 309 KB

Proton spin-lattice, T~, and spin-spin, T 2, relaxation times of highly stretched isotactic polypropylene film were measured in the temperature range 40-110°C. There is a monotonical increase in T~, when measured at 40°C, as the stretching ratio is increased. A shorter T I, Tis, was observed for all

Proton spin–lattice and spin–spin relaxa
Proton spin–lattice and spin–spin relaxation times in isotactic polypropylene. II. Effects of stretching ratio and temperature
✍ Hiroshi Tanaka 📂 Article 📅 1983 🏛 John Wiley and Sons 🌐 English ⚖ 383 KB 👁 2 views

Proton spin-lattice, T I , and spin-spin, Tz, relaxation times of uniaxially stretched polypropylene film were measured at 40°C using a wide line pulse spectrometer operating at 19.8 MHz. T11, the longer T I , increases almost linearly with increasing stretching ratio, and Tza, Tz of the amorphous r

Magnetic field dependence of proton spin
Magnetic field dependence of proton spin-lattice relaxation times
✍ Jean-Pierre Korb; Robert G. Bryant 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 105 KB 👁 1 views

The magnetic field dependence of the water-proton spin-lattice relaxation rate (1/T(1)) in tissues results from magnetic coupling to the protons of the rotationally immobilized components of the tissue. As a consequence, the magnetic field dependence of the water-proton (1/T(1)) is a scaled report o

Temperature dependence of the proton spi
Temperature dependence of the proton spin-spin relaxation time in liquid chloroform
✍ Dinesh; M.T. Rogers 📂 Article 📅 1971 🏛 Elsevier Science 🌐 English ⚖ 254 KB

The proton spin-spin rebxation time for liquid chloroform has been measured over the temperature range -54" to +9O"C. The values of Ta(H) decrease with increasing temperature contrary to the behavior obsemed for Tr (H). Values of Tz (I-l) calculated from experimental values of Tr (H) and Tz(Cl) repr