Effect of temperature and catalyst concentration on molecular weight during polymerization of trioxane in solution

Rakova, G. V.; Shaginyan, A. A.; Yenikolopyan, N.S.

doi:10.1016/0032-3950(67)90162-1

Cited by 6 publications

(10 citation statements)

References 8 publications

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“…Higher temperature leads to more agglomeration for a given polymer chain length because of the increase in amplitude of the Hamaker constant and subsequently the van der Waals potential as seen in eq . However, high temperature leads to shorter polymer chains for in situ polymerization . This means that when designing actual physical experiments, it is important to optimize the in situ polymerization temperature to produce the smallest agglomerates possible.…”

Section: Results and Discussionmentioning

confidence: 99%

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Monte Carlo Simulation Modeling of Nanoparticle–Polymer Cosuspensions

Gervasio

2018

Langmuir

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Creation of high-quality and novel polymer–particle nanocomposites to a large extent depends on understanding the behaviors of individual polymer chains and particles, especially at the mixing state in a liquid solvent. Simulations can help identify critical parameters and equations that govern the suspension behaviors. This study is the first attempt to understand the agglomeration processes of ZnO nanoparticle and poly(methyl methacrylate) polymer cosuspensions through a constant number Monte Carlo simulation. A modified Derjaguin–Landau–Verwey–Overbeek theory is used to describe the particle–particle interactions that lead to agglomeration. The average agglomerate size and number are measured as a function of suspension resting time, particle to polymer volume ratio, polymer chain length, and suspension drying. The agglomerate size increases persistently with the resting time and particle content increase, ranging from 1.2 μm for the 1 vol % particle content suspension to 4.6 μm for the 20 vol % particle content suspension after 30 min of suspension resting. The agglomerate size distribution for all of the particle contents follows a lognormal distribution. As the polymer chain length increases, agglomeration also becomes more severe. If drying is accounted for and thus the solids loading continually increases, the suspension becomes much more stable because of increases in viscosity and depletion stabilization.

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Section: Results and Discussionmentioning

confidence: 99%

“…However, high temperature leads to shorter polymer chains for in situ polymerization. 47 This means that when designing actual physical experiments, it is important to optimize the in situ polymerization temperature to produce the smallest agglomerates possible.…”

Section: Resultsmentioning

confidence: 99%

Monte Carlo Simulation Modeling of Nanoparticle–Polymer Cosuspensions

Gervasio

2018

Langmuir

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“…Opposing relationships between catalyst concentration and molecular weight of various polymers have been presented in literature [5, 14, 15]. One of these investigations includes the analysis of trioxane monomer to p-chlorophenyldiazonium hexafluorophosphate catalyst molar ratios ranging from 5,000 to 20,000.…”

Section: Resultsmentioning

confidence: 99%

“…As the catalyst concentration continued to decrease with monomer to catalyst ratios between 8,000 and 20,000, the relationship to polymer molecular weight became directly proportional [14]. A range of different initiator concentrations tested with trioxane had no effect on the resulting poly(trioxane) MW in melt conditions, but the same range explored in solution caused a decrease in MW as the initiator concentration increased [15]. The type of catalyst used can also influence the relationship between catalyst concentration and MW.…”

Section: Resultsmentioning

confidence: 99%

Tuning properties of poly(ethylene glycol)- block -poly(simvastatin) copolymers synthesized via triazabicyclodecene

Asafo-Adjei

Dziubla

Puleo

2017

Reactive and Functional Polymers

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Simvastatin was polymerized into copolymers to better control drug loading and release for therapeutic delivery. When using the conventional stannous octoate catalyst in ring-opening polymerization (ROP), reaction temperatures ≥200 °C were required, which promoted uncontrollable and undesirable side reactions. Triazabicyclodecene (TBD), a highly reactive guanidine base organocatalyst, was used as an alternative to polymerize simvastatin. Polymerization was achieved at 150 °C using 5 kDa methyl-terminated poly(ethylene glycol) (mPEG) as the initiator. ROP reactions with 2 kDa or 550 Da mPEG initiators were also successful using TBD at 150 °C instead of stannous octoate, which required a higher reaction temperature. Biodegradability of the poly(simvastatin) copolymer in phosphate-buffered saline was also improved, losing twice as much mass than the copolymer synthesized via stannous octoate. The three copolymers exhibited modified rates of simvastatin release, demonstrating tunablity for drug delivery applications.

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“…Thus, in the 1960s it was shown, that the highest polymerization rate of trioxane, as well as molecular weight of the polymer obtained, was achieved, when reaction being carried out at 10°C [60]. Increase in the reaction temperature led to the significant downfall of both polymerization rate and the resulting molecular weight.…”

Section: Introductionmentioning

confidence: 95%

Thermo-responsive Ruthenium Dendrimer-based Catalysts for Hydrogenation of the Aromatic Compounds and Phenols

Караханов

Maximov

Zolotukhina

et al. 2016

J Inorg Organomet Polym

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In this work thermo-responsive ruthenium catalysts, based on the poly(propylene imine) dendrimers cross-linked with the poly(ethylene glycol) diglycidyl ether, have been prepared for the first time. The materials obtained were characterized by X-ray photoelectron spectroscopy and transmission electron microscopy, and tested in the phenol and benzene hydrogenation. Conditions for the metal impregnation into the polymeric matrix were demonstrated to have a great influence both on physical chemical properties of the synthesized catalysts (metal loading, mean particles size, surface structure etc.), and, as a consequence, on their hydrogenation activity and thermoresponsive properties.

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Effect of temperature and catalyst concentration on molecular weight during polymerization of trioxane in solution

Cited by 6 publications

References 8 publications

Monte Carlo Simulation Modeling of Nanoparticle–Polymer Cosuspensions

Monte Carlo Simulation Modeling of Nanoparticle–Polymer Cosuspensions

Tuning properties of poly(ethylene glycol)- block -poly(simvastatin) copolymers synthesized via triazabicyclodecene

Thermo-responsive Ruthenium Dendrimer-based Catalysts for Hydrogenation of the Aromatic Compounds and Phenols

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