An HF-Nickel-R3Al Catalyst System for Producing High Cis-1,4-Polybutadiene

1972 ◽  
Vol 45 (1) ◽  
pp. 268-277 ◽  
Author(s):  
M. C. Throckmorton ◽  
F. S. Farson
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
High Molecular Weight ◽  
Catalyst Concentration ◽  
Dynamic Properties ◽  
Catalyst System ◽  
Polymerization Temperature

Abstract A relatively new, high cis-1,4-polybutadiene and a novel trialkylaluminumnickel-HF catalyst system have been described. This polybutadiene is unique in that it possesses high tack and has exceptionally good processing qualities; the carbon black-loaded and cured rubber possesses good static and dynamic properties. The catalyst system is very effective for producing high molecular weight rubber, suitable for oil extension, and the molecular weight can be controlled by adjusting 1) HF to R3Al ratio, 2) total catalyst concentration and/or 3) polymerization temperature.

scholarly journals A Complexed Initiating System AlCl3·Phenetole/TiCl4·H2O with Dominant Synergistic Effect for Efficient Synthesis of High Molecular Weight Polyisobutylene

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2121
Author(s):  
Yulong Jin ◽  
Liang Chen ◽  
Xing Guo ◽  
Linfeng Xu ◽  
Zhihua Zhu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Synergistic Effect ◽  
High Molecular Weight ◽  
Monomer Concentration ◽  
Catalyst System ◽  
Polymerization Temperature ◽  
Simple Preparation ◽  
Order Of Magnitude ◽  
Unique Approach ◽  
High Molecular Weight Polyisobutylene

A complexed initiating system AlCl3·phenetole/TiCl4·H2O was prepared by simply compounding AlCl3/phenetole and TiCl4/H2O and used for cationic polymerization of isobutylene. It was found AlCl3·phenetole/TiCl4·H2O exhibited activities 1.2–3 times higher than those of AlCl3/phenetole, and more than an order of magnitude higher than those of TiCl4/H2O, which indicated a notable synergistic effect produced in the complexed system. In addition, due to the higher activity of AlCl3·phenetole/TiCl4·H2O, lower coinitiator concentration and polymerization temperature, as well as higher monomer concentration were more favored for this complexed initiating system to produce polyisobutylene (PIB) with reasonable molecular weight (Mw) and molecular weight distribution (MWD). Furthermore, high molecular weight polyisobutylene (HPIB) with Mw = 1–3 × 105 g·mol−1 could be successfully produced by the complexed catalyst system at Tp = −60 to −40 °C. As a whole, the high activity as well as the simple preparation procedures of the complexed initiating system offer us a unique approach for the production of HPIB with improved efficiency.

Mixing of Carbon Black with Rubber. VI. Analysis of NR/SBR Blends

1988 ◽  
Vol 61 (4) ◽  
pp. 609-618 ◽  
Author(s):  
George R. Cotten ◽  
Lawrence J. Murphy
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
High Molecular Weight ◽  
Surface Area ◽  
Bound Rubber ◽  
Very High

Abstract The distribution of carbon black in NR/SBR blends was determined through the analysis of bound rubber. The NR/SBR blends were found to be very different from the previously studied SBR/BR compounds: these differences were assigned to mutual insolubility of the two polymers and a very high molecular weight of NR. In NR/SBR blends, it was found that changes in molecular weight of the polymer has no effect on the carbon black distribution in the blend. While the “activity” of carbon black did not affect the distribution, the loading of the black in NR decreased linearly with increasing surface area of the black. Approximately 35% of normal tread blacks (surface area 80–100 m2/g) was found in the NR phase. However, the bond between NR and carbon black is quite weak, and black continues to migrate into the SBR phase on prolonged mixing or during blending of NR and SBR masterbatches.

Preparation of syndiotactic polystyrene using novel monotitanocene with ortho-substituted phenoxy ligands

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Ling Zhang ◽  
Shanshan Xiao ◽  
Shaowen Huang ◽  
Fangming Zhu ◽  
Qing Wu
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Catalytic Properties ◽  
Syndiotactic Polystyrene ◽  
Polymerization Temperature ◽  
Cp Ti

Abstract Four new Cp*Ti compounds with ortho-substituted phenoxy ligands for the syndio- specific polymerization of styrene were prepared by the reaction of various kinds of ortho- substituted phenol with Cp*TiCl3 in the presence of triethylamine. Their catalytic properties for syndiospecific polymerization of styrene were investigated at different AlMAO/Ti ratio, different AlTIBA/Ti ratio and different polymerization temperature. All four compounds in the presence of cocatalyst methylaluminoxane (MAO) and triisobutylaluminum (TIBA) showed good performance at lower concentrations of titanium, MAO, and TIBA. Especially, ( Cp*Ti(OPhMe)3)/MAO system afforded syndiotactic polystyrene (sPS) with the highest activity and high molecular weight.

CIS-1,4 Polyisoprene Prepared with Alkyl Aluminum and Titanium Tetrachloride

1958 ◽  
Vol 31 (4) ◽  
pp. 838-846 ◽  
Author(s):  
H. E. Adams ◽  
R. S. Stearns ◽  
W. A. Smith ◽  
J. L. Binder
Keyword(s):  
Molecular Weight ◽  
Carbon Black ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Room Temperature ◽  
Titanium Tetrachloride ◽  
Polymerization Temperature ◽  
Solution Polymerization ◽  
Lower Temperature ◽  
Hysteretic Properties

Abstract By adjustment of the relative amounts of the two components of the catalyst and the temperature of polymerization, cis-1,4 polyisoprene can be produced free from trans-1,4 configuration. Catalysts containing a mole ratio of alkyl aluminum to titanium tetrachloride of 1.0 produce polymers with this configuration at room temperature. At lower temperature of polymerization, somewhat higher ratios are needed to achieve the same result. Solution polymerization was used to control the reaction and obtain a uniform product. It was necessary to use 3 to 5 phm of total catalyst to obtain 100 per cent yield in 4 hours at room temperature. The inherent viscosity of the polymers made under these conditions is low, usually 2.0 to 2.5. However, higher molecular weight polymers are produced at lower polymerization temperature. Compounding studies indicate that vulcanizates of these polymers possess both normal and hot tensile properties comparable to natural rubber. Hysteretic properties of the carbon black vulcanizates of the polymers studied are inferior to those of natural rubber.

Synthesis and characterization of high molecular weight and low dispersity polystyrene homopolymers by RAFT polymerization

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Cheng Jin ◽  
Chun Liu ◽  
Bo Jiang ◽  
Qin-jian in
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymerization Temperature ◽  
Polymer Molecular Weight ◽  
Mild Conditions ◽  
Reversible Addition ◽  
Polymerization Method

AbstractHigh molecular weight polystyrene homopolymers with low dispersity were synthesized by a reversible addition-fragmentation chain transfer (RAFT) polymerization method using 0.03 and 0.3 wt% of cumyl dithiobenzoate (CDB) vs. styrene (St) and the azobis(isobutyronitrile) initiator, at the polymerization temperature of 60 or 70 °C. The optimal high molecular weight polystyrene via this synthetic scheme shows Mw = 46.5×104, Mn = 33.3×104, and a dispersity of 1.40. The polystyrene chain contains a dithiobenzoate C=S moiety and thus can be used as a macro-chain-transfer agent for the polymerization of other monomers and for the synthesis of diversified block copolymers under mild conditions. The changes of the polystyrene molecular weight and dispersity were studied by the influences of the initial concentration ratio of CDB to styrene ([CDB]0/[St]0), the polymerization temperature, and the polymerization time. The PS molecular weight is inversely proportional to the [CDB]0/[St]0 ratio. Decreasing CDB from 0.3 to 0.03 wt%, a high MW PS was obtained, while the dispersity was observed to increase from 1.10 to 1.40. The PS molecular weight increases with the increase of the reaction time, while the dispersity of PS varies little from 1.12 to 1.23. The molecular weight and dispersity increase with the increase of the polymerization temperature. As the temperature arises from 60°C to 70°C, the conversion increases considerably from 25.8% to 39.9%, and the dispersity increases slightly from 1.15 to 1.17. As the temperature reaches 80°C, the conversion increases considerably to 64.7%, and the dispersity increases to 1.53. The polymer molecular weight of the polystyrene prepared by the RAFT method is suitable for the applications of engineering materials.

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