Results 191 to 200 of about 2,946 (246)

Prepolymerization of ethylene with a Ziegler–Natta catalyst

Journal of Applied Polymer Science, 2007
AbstractThe slurry prepolymerization of ethylene using TiCl4/MgCl2 as a catalyst was investigated. A 23‐factorial experimental design method was employed to study the effects of the temperature, hydrogen, and active cocatalyst‐to‐catalyst molar ratio (Al/Ti) on the catalyst activity, prepolymer melt flow index, and powder bulk density.
Ahmad Mirzaei, Mohammad Vakili, Neda Tafi   +2 more
openaire   +2 more sources

Linear segmented polyurethanes. II. A mathematical model for the prepolymerization stage

Journal of Applied Polymer Science, 2018
ABSTRACTIn the first part of this sequel, an experimental investigation on the synthesis of linear segmented polyurethanes was presented, that included estimation of the kinetic constants at 60°C for the prepolymerization and finishing stages. This work presents two comprehensive mathematical models that simulate the mentioned prepolymerizations, in ...
M. L. Polo, J. I. Pesoa, V. V. Nicolau, M. E. Spontón, D. A. Estenoz, G. R. Meira   +5 more
openaire   +3 more sources

Evidence of Liquid-Liquid Demixing During Bi-Soft Segment Polyurethane Prepolymerization

Macromolecular Research, 2018
Bi-soft segment isocyanate-terminated polyurethanes (ITPUs) currently play a major role in the industrial production of high performance polyurethanes (adhesives, coating, foams, thermoplastics, nanoparticles, dispersion). The present contribution reports on the investigation of liquid-liquid demixing phenomena during the synthesis of bi-soft segment ...
Christian Wenning, Jens Noe, Stéphan Barbe, Marc C. Leimenstoll   +3 more
openaire   +2 more sources

Synthesis of prepolymerization stage in polycondensation processes

AIChE Journal, 1999
AbstractA systematic design procedure of the prepolymerization stage of a polycondensation process is presented. This procedure treats polycondensation processes as reactive separation processes and offers an alternative to design through simulations.
Ketan D. Samant, Ka M. Ng
openaire   +2 more sources

Synthesis of palm-based polyurethane-LiClO4 via prepolymerization

AIP Conference Proceedings, 2015
Palm-based polyurethane (pPU) with varying lithium salt (LiClO4) content was synthesized. Higher loading percentage of LiClO4 in the pPU led to the inhibition of prepolymerization process from taking place. Hydrogen bonded C=O was detected in the FTIR spectrum indicating the hydrogen bonding between the urethane bonds.
Jason Wong Chee Sien, Khairiah Haji Badri, Mohd. Sukor Su’ait, Nurul Izzati Hassan   +3 more
openaire   +2 more sources

Graphene/MWNT/Poly(p-phenylenebenzobisoxazole) Multiphase Nanocomposite via Solution Prepolymerization with Superior Microwave Absorption Properties and Thermal Stability

, 2016
Jiasong Hua, Yanxiao Li, Xiaoyun Liu, Xinxin Li, Shaoliang Lin, Jinlou Gu, Zhong‐Kai Cui, Qixin Zhuang   +7 more
openalex   +2 more sources

Inorganic and Prepolymerized Filler Analysis of Four Resin Composites

Operative Dentistry, 2013
SUMMARY This study determined the filler content by weight percentage of four resin composites and examined the morphology, size, and elemental distribution of the filler particles. Four commercially available light-cured resin composites were evaluated for filler content by weight using ashing in air and acetone dissolution techniques ...
D C, Salazar, J, Dennison, P, Yaman
openaire   +2 more sources

NMR study of PMR‐15 prepolymerization steps

Journal of Polymer Science Part A: Polymer Chemistry, 1994
AbstractVariations in PMR‐15 composites properties could be due to differences in their chemical compositions occurring during the curing cycle. Variations in the composition of the PMR‐15 resin were studied for four different curing cycles, to determine the influences of parameters such as the heating rate or the presence of a temperature stage.
A. Milhourat‐Hammadi, H. Chayrigues, C. Merienne, A. Gaudemer   +3 more
openaire   +1 more source

Coagulation with Prepolymerized Metal Salts

1990
It has been known to mankind for 4000 years that alum and iron are useful in the treatment of water. Purified alum was, however, first manufactured in the fifteenth century. In England, treatment of muddy waters by coagulation/flocculation started in the mid-seventeenth century.
Hallvard Ødegaard, Joachim Fettig, Harsha C. Ratnaweera   +2 more
openaire   +1 more source

Influence of prepolymerization on gelation of diepoxide-diamine systems

Polymer, 1992
Abstract The polymerization of diepoxide-diamine is simulated using a two-stage procedure. In the first stage a convenient epoxy or amine excess is used to prepare a liquid prepolymer at complete conversion, which is then cured in a second step by balancing stoichiometry.
Carmen C. Riccardi, Roberto J.J. Williams   +1 more
openaire   +1 more source