Search results for "Bulk polymerization"

Novel diamine-bis(phenolate) Ti(IV) complexes – tuning the complex structure to control catalytic properties in α-olefin polymerization

2016

Abstract Four monomeric titanium(IV) dichloride complexes of amine-bis(phenolate) ligands having an extra donor arm (2a–2d) and one oxo-bridged complex 3 were successfully synthesized in the reaction of TiCl4 with a sodium salt of the appropriate ligand, and they were characterized by 1H NMR spectroscopy. The ligands had either a dimethylamino side‐arm donor and t-Bu substituents on both (1a) and one (1d) phenolate rings or a diisopropylamino side-arm donor and t-Bu (1b) and t-Bu along with OMe (1c) phenolate substituents. All complexes upon activation with [Ph3CB(C6F5)4] and MAO were used to catalyze polymerization of 1-octene (in liquid monomer) into poly(1-octene). Their activities as we…

A continuous reaction system to investigate dispersion polymerization of vinyl monomers in supercritical carbon dioxide

2006

A laboratory-scale continuous reaction system using a stirred tank reac- tor was assembled in our laboratory to study the dispersion polymerization of vinyl monomers in supercritical carbon dioxide (scCO2). The apparatus was equipped with a suitable downstream separation section to collect solid particles entrained in the effluent stream from the reactor, whose monomer concentration could be measured online with a gas chromatograph. The dispersion polymerization of methyl methacry- late in scCO2 was selected as a model process to be investigated in the apparatus. The experiments were performed at 65 8C and 25 MPa with 2,2 0 -azobisisobutyroni- trile as the initiator and a reactive polysilox…

Polyreactions in ordered systems: Polymerization of octadecyl methacrylate in monolayers at the gas–water interface

1977

The ultraviolet-initiated polymerization of octadecyl methacrylate (ODMA, octadecyl 2-methyl-2-propenoate) as a monomolecular layer at the gas-water interface was studied. The polymerization was carried out at 27°C at the nitrogen-water interface; air inhibits the polymerization. At 27°C the ODMA monolayer exhibits three different states which were characterized by surface pressure-area diagrams and by surface potential measurements. The ODMA monolayer was polymerized under constant surface pressure in the range between 0 and 10 dyne/cm. The polymerization was followed by recording the contraction of the film. The conversion was determined by comparison of the area per monomer unit during p…

Design, Synthesis, and Use of Y-Shaped ATRP/NMP Surface Tethered Initiator.

2015

Heterogeneous polymer brushes on surfaces can be easily formed from a binary initiator on a silicon oxide substrate where two different types of polymers can be grown side-by-side. Herein, we designed a new Y-shaped binary initiator using straightforward chemistry for “grafting from” polymer brushes. This initiator synthesis takes advantage of the Passerini reaction, a multicomponent reaction combining two initiator sites and one surface linking site. This Y-shaped binary initiator can be synthesized in three steps with a higher yield than other similar initiators reported in the literature, and can be performed on a multigram scale. We were able to attach the initiator to a silicon oxide s…

Patterning of a Surface Immobilized ATRP Initiator with an Inkjet Printer

2010

A new technique for patterning polymer brushes on the micrometer scale has been developed in which an inkjet printer was used to deposit droplets of acid on a surface-immobilized initiator for atom transfer radical polymerization (ATRP). The acid cleaved an ester bond in the ATRP initiator in a saponification reaction. As a result, the ATRP initiator was rendered inactive. To control the degree of defunctionalization, a new initiator containing a weak ester bond was derived from a tertiary alcohol. Comparison to an established ATRP initiator, derived from a primary alcohol, showed that the novel initiator was defunctionalized with a higher efficiency. Control of the reaction time allowed to…

Molecular Weight Distribution of Hyperbranched Polymers Generated by Self-Condensing Vinyl Polymerization in Presence of a Multifunctional Initiator

1999

The molecular weight distribution (MWD) is derived for polymers generated by self-condensing vinyl polymerization (SCVP) of a monomer having a vinyl and an initiator group (“inimer”) in the presence of a multifunctional initiator. If the monomer is added slowly to the initiator solution (semi-batch process), this leads to hyperbranched polymers with a multifunctional core. If monomer and initiator are mixed simultaneously (batch process), even at vinyl group conversions as high as 99%, the total MWD consists of polymers which have grown via reactions between inimer molecules (i.e., the normal SCVP process) and those which have reacted with the initiator. Consequently, the weight distributio…

Die polymerisation und pfropf-mischpolymerisation des acroleins unter dem einfluß von Co - 60 - gamma - strahlen. Polymere acroleine. 14. Mitteilung

1959

Die Polymerisation des Acroleins im reinen Zustand und in Losung unter dem Einflus von γ-Strahlen wird beschrieden und mit anderen Polymerisations-Methoden verglichen. Bei der Block-Polymerisation entsteht ein stark vernetztes, glasartiges Polymerisat, das in wasriger schwefliger Saure unloslich ist. In Losung polymerisiert das Acrolein viel rascher; die relative Geschwindigkeit der Polymerisation ist am grosten in wasriger Losung. Das hier erhaltene Polymere enthalt reaktionsfahige Aldehyd-Gruppen und ist loslich in schwefliger Saure. Acrolein last sich auf Polymethacrylester aufpfropfen. Sowohl oberflachliche als auch durchgehende Pfropfung vorgeformter Proben des Polymethacrylesters ist …

1977

The solution polymerization of styrene in methylene dichloride catalysed by trifluoromethanesulfonic acid takes place at a high rate even at low catalyst concentration. The S-shaped course of the conversion curves is explained by a reaction mechanism, in which the catalyst rapidly forms an inactive complex with one monomer molecule, and this monomer-acid complex is in equilibrium with the free catalyst molecule from which the propagating species are formed. Therefore, the formation of active initiating species becomes a slow process which depends also on the change of monomer concentration during polymerization. It is assumed that the active initiating species are formed from two or three m…

Die thermische Polymerisation von Methylmethacrylat, 1. Polymerisation in Substanz

1978

Special purification of the monomer and careful preparation of the reaction setup allowed a thorough study of the spontaneous thermal polymerization of methyl methacrylate over a wide range of temperatures (0–140°C). The rates of polymerization are notably lower than the few data previously reported in literature, and the degrees of polymerization slightly higher. The thermal initiation reaction is superimposed by radical production due to the natural ionising radiation (cosmic radiation etc.). This additional initiation becomes significant at temperatures below 60°C. New and more reliable monomer chain transfer constants are given.

Anionische Polymerisation in Schwach Solvatisierenden Lösungsmitteln

2007

The anionic polymerization of styrene initiated by cumylsodium and carried out in cumyl methyl ether has been examined with use of conversion kinetics and molecular weight distribution. The solvent has a weaker solvation power than THF and THP, which have been studied with the same experimental technique. The polymerization rate is first order relative to monomer and the rate constant has a value of ca. 1 mole−1 1. sec.−1 at − 20.5°C. The constant is only slightly dependent on the initiator concentration, but the molecular weight distribution is broader than a Poisson function. Added electrolyte has little effect on the propagation constant but it greatly alters the molecular weight distrib…