Results 191 to 200 of about 23,452,503 (249)

Nucleation Mechanism for Form II to I Polymorphic Transformation in Polybutene-1

Macromolecules, 2020
By means of in situ small-/wide-angle X-ray scattering (SAXS/WAXS) techniques, nucleation mechanism for Form I crystals of polybutene-1 (PB-1) has been investigated by heating the early-stage polym...
Binghua Wang, Kangzhu He, Yaguang Lu, Yufeng Zhou, Jinlong Chen, C. Shen, Jingbo Chen, Yongfeng Men, Bin Zhang   +8 more
semanticscholar   +1 more source

Effects of molecular weight on polybutene-1 cold crystallization from polybutene-1/polypropylene blend

Polymer, 2019
Abstract The influence of molecular weight on the polymorphic behavior of polybutene-1 (PB-1) in cold crystallization from PB-1/iPP (isotactic polypropylene) blend has been investigated. Twelve PB-1/iPP blend samples of 90/10 (w/w) composition were prepared from three PB-1s and four iPPs with molecular weight of 77–711 kg/mol and 12–580 kg/mol ...
Zhaohui Su, Zhaohui Su, Zhenxing Zhong, Zhenxing Zhong   +3 more
openaire   +2 more sources

Time dependent crystallinity of polybutene‐1

Polymer Engineering & Science, 1966
AbstractIsotactic Polybutene‐1 can exist in 4 different crystalline phases of varying stability of which two are of greatest importance because they are involved in solidification from the melt initially, the melt cools into an unstable crystalline phase which gradually and spontaneously transforms into a stable, stronger, stiffer, more crystalline ...
S. Y. Choi, J. P. Rakus, J. L. O'Toole
openaire   +2 more sources

Annealing Behavior of Isotactic Polybutene-1

Journal of Macromolecular Science: Part A - Chemistry, 1987
The annealing behavior of isotactic polybutene-1 (PB-1) has been studied by differential scanning calorimetry and wide-angle x-ray diffraction. On annealing at 110°C, PB-1 yields thick crystals melting at -140°C which are mainly of Form I. An increase in the heat of fusion (ΔHf) and crystallinity is found for annealing times up to 12 h at 110°C; at ...
Kishore, K, Vasanthakumari, R
openaire   +2 more sources

Annealing of polybutene‐1 single crystals

Journal of Polymer Science Part A-2: Polymer Physics, 1968
AbstractThe effects of thermal treatment in the 70–90°C. region on polybutene‐1 crystals, prepared by precipitation from dilute pentyl acetate solutions and with lath, hexagonal, and square morphologies, have been studied by using electron microscopy.
D. R. Morrow, A. E. Woodward
openaire   +2 more sources

Promotion of Form I′ in the Polymorph Selection of Polybutene-1 during Crystallization under High Gas/Supercritical Fluid Pressure via Enhancing Chain Mobility

, 2020
Polybutene-1 (PB-1) always crystallizes into its metastable form II when cooled from a molten state because of its lower nucleation barrier, while the stable form I exhibits superior properties com...
Yongna Qiao, Jing Liu, Jinchuan Zhao, Menglong Xu, Qing Qi, Zuolong Chen, Yongfeng Men, Chul B. Park, Patrick C. Lee   +8 more
semanticscholar   +1 more source

Infrared characterization of polymorphism in polybutene‐1

Journal of Polymer Science Part A-2: Polymer Physics, 1966
AbstractThe transformations of the polymorphic forms of polybutene‐1 (I,II,III) were studied by infrared spectroscopy. Attenuated total reflectance spectra demonstrate that the II → I transformation occurs initially and most rapidly on the film surfaces. Electron irradiation experiments showed the II → I conversion can be suppressed by irradiation. The
R. Salovey, J. P. Luongo
openaire   +2 more sources

Local deformation in stretched polybutene‐1 spherulites

Journal of Polymer Science Part A-2: Polymer Physics, 1970
AbstractThe orientation of crystals in spherulites of modifications I and II of polybutene‐1 was studied by micro‐x‐ray diffraction. Changes in such micro‐x‐ray diffraction patterns were measured in various regions of the spherulites as a function of strain and time. The relationship between micro‐x‐ray diffraction from parts of spherulites and macro‐x‐
R. Y. Yee, Richard S. Stein
openaire   +2 more sources

Preparation of high isotactic polybutene-1

Journal of Applied Polymer Science, 2000
Polymerization of butene-1 (B-1) was carried out with a PP-TiCl3/Et2AlCl/methyl methacrylate (MMA) catalyst system in n-heptane. The influence of temperature, pressure, time and H2 on molecular weight, isotacticity, and catalytic activity were studied by viscometry, solubility in boiling diethyl ether, and measuring the polymer produced, respectively ...
N. Sharifi-Sanjani, S. Abedi
openaire   +2 more sources

Retardance of Form II to Form I Transition in Polybutene-1 at Late Stage: A Proposal of a New Mechanism

, 2018
The retardation of polybutene-1 form II to form I transition in the late stage has been investigated by means of time-resolved wide-angle X-ray diffraction.
Yongna Qiao, Hai Wang, Yongfeng Men
semanticscholar   +1 more source