In-situ Titration of Initiator-Consuming Impurities in Solution Anionic Polymerization

1993 ◽  
Vol 66 (4) ◽  
pp. 588-593 ◽  
Author(s):  
V. M. Monroy ◽  
G. Guevara ◽  
I. Leon ◽  
A. Correa ◽  
R. Herrera
Keyword(s):  
Anionic Polymerization ◽  
Polymerization Reaction ◽  
Molecular Weights

Abstract An in situ titration of initiator-consuming impurities in amonic polymerizations, using 1,10-phenantroline as an indicator, was developed. The results show that even when impurities are present, it is possible to destroy them prior to the initiation of the polymerization reaction and achieve a better control of molecular weights by adding accurate known quantities of initiator.

Dialkoxy-Substituted, C1-Symmetric Metallocenes: Synthesis and Catalytic Behavior in the Propylene Polymerization Reaction

2004 ◽  
Vol 59 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Martin Schlögl ◽  
Bernhard Rieger
Keyword(s):  
Chain Transfer ◽  
Active Catalyst ◽  
Propylene Polymerization ◽  
Polymerization Reaction ◽  
Catalytic Behavior ◽  
Molecular Weights ◽  
Hydrocarbon Solvents ◽  
In Situ Activation ◽  
Reversible Chain Transfer

The synthesis of a series of C1-symmetric metallocene complexes rac-[1-(5,6-dialkoxy-2-methyl- 1-η5-indenyl)-2-(9-η5-fluorenyl)ethane]zirconium dichlorides (alkyl: n-butyl, n-hexyl, n-octyl, n-decyl) is described. These complexes are versatile catalysts in the polymerization of propylene after in situ activation with triisobutylaluminum (TIBA) and Ph3C[B(C6F5)4] in toluene and heptane solution. All catalysts show higher solubility and improved polymerization properties in industrially used hydrocarbon solvents (e.g. heptane). However, the molecular weights and isotacticity values of the resulting polypropylene materials are decreased compared to the ethoxy-bridged analogue rac- [1-(5,6-ethylenedioxy-2-methyl-η5-indenyl)-2-(9-η5-fluorenyl)ethane]zirconium dichloride. A possible explanation is based on enhanced interaction of the active catalyst centers with Al(III) scavenger molecules even at low Al : Zr ratios, leading to reversible chain transfer.

scholarly journals Sustainable Myrcene-Based Elastomers via a Convenient Anionic Polymerization

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 838
Author(s):  
David Hermann Lamparelli ◽  
Magdalena Maria Kleybolte ◽  
Malte Winnacker ◽  
Carmine Capacchione
Keyword(s):  
Anionic Polymerization ◽  
Sodium Hydride ◽  
Reactivity Ratios ◽  
Molecular Weights ◽  
Styrene Copolymers ◽  
Wide Range ◽  
Elastomeric Materials ◽  
Complete Study ◽  
Anionic Copolymerization ◽  
Trialkylaluminum Derivatives

Soluble heterocomplexes consisting of sodium hydride in combination with trialkylaluminum derivatives have been used as anionic initiating systems at 100 °C in toluene for convenient homo-, co- and ter-polymerization of myrcene with styrene and isoprene. In this way it has been possible to obtain elastomeric materials in a wide range of compositions with interesting thermal profiles and different polymeric architectures by simply modulating the alimentation feed and the (monomers)/(initiator systems) ratio. Especially, a complete study of the myrcene-styrene copolymers (PMS) was carried out, highlighting their tapered microstructures with high molecular weights (up to 159.8 KDa) and a single glass transition temperature. For PMS copolymer reactivity ratios, rmyr = 0.12 ± 0.003 and rsty = 3.18 ± 0.65 and rmyr = 0.10 ± 0.004 and rsty = 3.32 ± 0.68 were determined according to the Kelen–Tudos (KT) and extended Kelen–Tudos (exKT) methods, respectively. Finally, this study showed an easy accessible approach for the production of various elastomers by anionic copolymerization of renewable terpenes, such as myrcene, with commodities.

scholarly journals Effects of Molecular Weight of Functionalized Liquid Butadiene Rubber as a Processing Aid on the Properties of SSBR/Silica Compounds

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 850
Author(s):  
Donghyuk Kim ◽  
Byungkyu Ahn ◽  
Kihyun Kim ◽  
JongYeop Lee ◽  
Il Jin Kim ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Anionic Polymerization ◽  
High Performance ◽  
Crosslink Density ◽  
Functional Group ◽  
Vital Role ◽  
Butadiene Rubber ◽  
Molecular Weights ◽  
Mooney Viscosity ◽  
Silica Dispersion

Liquid butadiene rubber (LqBR) which used as a processing aid play a vital role in the manufacturing of high-performance tire tread compounds. However, the studies on the effect of molecular weight, microstructure, and functionalization of LqBR on the properties of compounds are still insufficient. In this study, non-functionalized and center-functionalized liquid butadiene rubbers (N-LqBR and C-LqBR modified with ethoxysilyl group, respectively) were synthesized with low vinyl content and different molecular weights using anionic polymerization. In addition, LqBR was added to the silica-filled SSBR compounds as an alternative to treated distillate aromatic extract (TDAE) oil, and the effect of molecular weight and functionalization on the properties of the silica-filled SSBR compound was examined. C-LqBR showed a low Payne effect and Mooney viscosity because of improved silica dispersion due to the ethoxysilyl functional group. Furthermore, C-LqBR showed an increased crosslink density, improved mechanical properties, and reduced organic matter extraction compared to the N-LqBR compound. LqBR reduced the glass transition temperature (Tg) of the compound significantly, thereby improving snow traction and abrasion resistance compared to TDAE oil. Furthermore, the energy loss characteristics revealed that the hysteresis loss attributable to the free chain ends of LqBR was dominant.

Synthesis of a sequence-controlled in-chain alkynyl/tertiary amino dual-functionalized terpolymer via living anionic polymerization

2018 ◽  
Vol 9 (1) ◽  
pp. 108-120 ◽  
Author(s):  
Lincan Yang ◽  
Hongwei Ma ◽  
Li Han ◽  
Xinyu Hao ◽  
Pibo Liu ◽  
...  
Keyword(s):  
Anionic Polymerization ◽  
Kinetic Characteristics ◽  
Living Anionic Polymerization ◽  
Sequence Structure ◽  
H Nmr ◽  
Nmr Method ◽  
Tertiary Amino

A dual-functionalized sequence-defined terpolymer was synthesized via living anionic polymerization; meanwhile its kinetic characteristics and sequence structure were investigated in detail via the in situ1H NMR method.

scholarly journals Investigation of Silicon Nanoparticle-Polystyrene Hybrids

2019 ◽  
Vol 2 (2) ◽  
pp. 49-50
Author(s):  
Madihah Khan ◽  
Alyxandra Thiessen ◽  
I Teng Cheong ◽  
Sarah Milliken ◽  
Jonathan G. C. Veinot
Keyword(s):  
Silicon Nanoparticles ◽  
In Situ Polymerization ◽  
Toxic Substance ◽  
Homogeneous Mixture ◽  
Silicon Nanoparticle ◽  
Molecular Weights ◽  
Abundant Element ◽  
The Stability ◽  
Led Lights

Current LED lights are created with quantum dots made of metals like selenium, tellurium, and cadmium which can be toxic. Silicon is used as a non-toxic substance and is the second most abundant element in the earth's crust. When silicon is prepared at a nanometer size, unique luminesce optical properties emerge that can be tuned using sized surface chemistry. Therefore, silicon nanoparticles can be used as an alternative emitter for LED lights. To produce hydride-terminated silicon nanoparticles we must synthesize the particles. Hydrogen silsesquioxane (HSQ) is processed at 1100 °C for one hour causing Si to cluster and form a SiO2 matrix, also known as the composite. The composite is then manually crushed in ethanol. The solution is further ground using glass beads, then filtered to get the composite powder. The final step is the HF etching. The hydride-terminated particles are then functionalized using three different methods to synthesize silicon nanoparticle-polystyrene hybrids, which determine the magnitude of luminosity and the quality of the hybrids. We spin coat each method and results were analyzed. Method 1 uses heat to functionalize hydride-terminated silicon nanoparticles with styrene. This process also causes styrene to attach to styrene to form a polystyrene chain. Method 1 gave a homogeneous mixture which yielded a consistent, bright and homogenous film. In method 2, dodecyl-terminated silicon nanoparticles are mixed with premade polystyrene. While this method gave better control of the amount of silicon nanoparticles inside the polymer hybrid, a homogeneous mixture was not created due to the different structures of polystyrene and dodecyl chains. Method 3 has dodecyl-terminated silicon with in-situ styrene polymerization. It generated a homogeneous mixture. The in-situ polymerization stabilizes the particles, allowing for brighter luminescence. Because of the stability and lower molecular weight, the mixture was easier to dissolve. We concluded that the different methods resulted in different polymer molecular weights and this created distinct properties between the polymer hybrids when spin-coating.    

In Situ Study of The Exposure of Polycarbonate to an Argon Plasma

1995 ◽  
Vol 385 ◽  
Author(s):  
S. Vallon ◽  
B. Drevillon ◽  
F. Poncin-Epaillard ◽  
J. C. Rostaing
Keyword(s):  
Structural Changes ◽  
Argon Plasma ◽  
Silica Layer ◽  
Molecular Weights ◽  
In Situ Study ◽  
Polar Groups ◽  
Unit Scale ◽  
Two Populations ◽  
Polymer Unit

ABSTRACTThe exposure of polycarbonate to an argon plasma is studied using in situ ellipsometry from the UV to the IR, nuclear magnetic resonance and light scattering measurements. An increase in the refractive index and the existence of two populations of different molecular weights show that structural changes occur in the polymer. They are correlated with modifications at the polymer unit scale, such as formation of new polar groups and decrease in dimethyl groups. Two simultaneous reaction mechanisms must be considered to account for these changes. The adhesion of a silica layer on treated polycarbonate is then discussed.

scholarly journals Simultaneous in situ monitoring of acrylic acid polymerization reaction on N-carboxymethyl chitosan using multidetectors: Formation of a new bioadhesive and gastroprotective hybrid particle

2011 ◽  
Vol 31 (3) ◽  
pp. 677-682 ◽  
Author(s):  
Oscar D'Agostini-Junior ◽  
Carmen Lucia Petkowicz ◽  
Angelica Garcia Couto ◽  
Sergio Faloni de Andrade ◽  
Rilton Alves Freitas
Keyword(s):  
Acrylic Acid ◽  
Carboxymethyl Chitosan ◽  
In Situ Monitoring ◽  
Polymerization Reaction ◽  
Hybrid Particle

scholarly journals Synthesis and post-polymerization reaction of end-clickable stereoregular polymethacrylates via termination of stereospecific living anionic polymerization

2015 ◽  
Vol 6 (7) ◽  
pp. 1078-1087 ◽  
Author(s):  
Yasuhiro Kohsaka ◽  
Takashi Kurata ◽  
Kazuki Yamamoto ◽  
Shoya Ishihara ◽  
Tatsuki Kitayama
Keyword(s):  
Methyl Methacrylate ◽  
Anionic Polymerization ◽  
Polymerization Reaction ◽  
Living Anionic Polymerization ◽  
Poly Methyl Methacrylate ◽  
End Groups

Poly(methyl methacrylate)s with high stereoregularity and clickable end-groups were synthesized via terminating reactions with α-(halomethyl)acrylates in stereospecific living anionic polymerization.

scholarly journals Optical monitoring of polymerizations in droplets with high temporal dynamic range

2020 ◽  
Vol 11 (10) ◽  
pp. 2647-2656
Author(s):  
Andrew C. Cavell ◽  
Veronica K. Krasecki ◽  
Guoping Li ◽  
Abhishek Sharma ◽  
Hao Sun ◽  
...  
Keyword(s):  
Fluorescence Polarization ◽  
Dynamic Range ◽  
Polymerization Reaction ◽  
Optical Monitoring ◽  
Polarization Anisotropy ◽  
Temporal Dynamic ◽  
Reaction Progress ◽  
Aggregation Induced Emission ◽  
Fluorescence Polarization Anisotropy

Two complementary measurements, fluorescence polarization anisotropy and aggregation-induced emission, allow for in situ optical monitoring of polymerization reaction progress in droplets across varying temporal regimes of the reaction.

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