Synthesis and characterization of poly(methyl methacrylate) using monofunctional polyhedral oligomeric silsesquioxane as an initiator

Liu, Lei; Wang, Wenping

doi:10.1007/s00289-008-0020-0

Cited by 30 publications

(25 citation statements)

References 33 publications

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“…The measured PS and PMMA spectra exhibited characteristic FT-IR peaks such as 2000-1700, 1601, 1493, 1452, 749, and 696 cm − 1 for PS [ 33 , 34 ] and 2952, 2866, 1730, and 1147 cm − 1 for PMMA [ 35 ] ; the peak assignment is given in Table S1 (see Supporting Information). [ 36 ] Some noise is present around 2000-2300 cm − 1 associated with atmospheric carbon dioxide.…”

Section: Homopolymer Formationmentioning

confidence: 99%

Polystyrene‐block‐poly(methyl methacrylate): Initiation Issues with Block Copolymer Formation Using ARGET ATRP

Aitchison

Ginic‐Markovic

Clarke

et al. 2011

Macro Chemistry & Physics

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The synthesis, kinetics, and characterization of polystyrene and poly(methyl methacrylate) block copolymers produced by ARGET ATRP are discussed. Halogen exchange is used and the polymerization appears to be living in the generation of the second block. On further investigation, the GPC traces exhibit a shoulder, which suggests poor initiation of the macroinitiator. Previous reports suggest that to increase the initiation effi ciency of the second block, 10% styrene monomer should be added to the mixture. Upon adding the 10% styrene for the second block ARGET ATRP polymerization, the appearance of a well-initiated polymer is observed. However, at greater conversions the results clearly demonstrate the production of a homopolymer/block copolymer mixture.leading to polymer contamination. [ 12 ] Activators regenerated by electron transfer (ARGET) ATRP was developed to offset the sensitivity of normal ATRP. ARGET ATRP uses a reducing agent, often ascorbic acid [ 13 , 14 ] or tin(II) 2-ethylhexanoate [Sn(EH) 2 ], [ 15 , 16 ] to consume the oxygen impurities that can inhibit the polymerization, thus reducing the sensitivity of this novel living system. The ease of polymerization creates low polydispersity homopolymers with many uses in future applications. [ 17 , 18 ] Block copolymer polymerization requires effi cient initiation of the fi rst and second block so that a lowpolydispersity block copolymer is formed. After the fi rst block has been polymerized, it is used as the macroinitiator for the subsequent polymerization of a different monomer. However, the macroinitaitor is chemically different from the initiator originally used to synthesize the fi rst block. [ 19 , 20 ] It has been found that for normal ATRP the initiation equilibrium constants are of the following order: acrylonitrile > methacrylates > styrene ≈ acrylates > acrylamides > > vinyl chloride > vinyl acetate. This order must be obeyed to produce a well-initiated polymerization and hence growth from the macroinitiator [i.e., the poly(methyl methacylate) (PMMA) must be extended by

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Section: Homopolymer Formationmentioning

confidence: 99%

Polystyrene‐block‐poly(methyl methacrylate): Initiation Issues with Block Copolymer Formation Using ARGET ATRP

Aitchison

Ginic‐Markovic

Clarke

et al. 2011

Macro Chemistry & Physics

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“…[56][57][58][59][60][61][62][63][64][65] More recently, POSS nanocages, with a single polymerizable functional group per nanocage, have attracted significant attention for their potential in preparing welldefined organic-inorganic hybrid (co)polymers via living polymerization techniques. [66][67][68][69][70] However, little attention has been paid to amphiphilic block copolymers having POSS polymers as the hydrophobic block or their self-assembly.…”

Section: Introductionmentioning

confidence: 99%

Micelle Formation and Gelation of (PEG−P(MA-POSS)) Amphiphilic Block Copolymers via Associative Hydrophobic Effects

et al. 2010

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A series of well-defined amphiphilic di- and triblock copolymers have been synthesized, using atom transfer radical polymerization, with poly(ethylene glycol) (PEG) and poly(methacrylisobutyl polyhedral oligomeric silsesquioxane) P(MA-POSS) as the hydrophilic and hydrophobic blocks, respectively. The detailed self-assembly behavior of the amphiphilic macromolecules in aqueous media was studied using both static and dynamic light scattering (SLS and DLS) techniques. The evolution of block copolymer micelle formation in THF/water mixture (20/80 v/v) was monitored as the THF evaporated from the solvent mixture. Initially the block copolymer chains existed as unimers in solution, followed by the formation of smaller aggregates (R(h) < 2 nm) after 30 min, eventually growing in size to reach an equilibrium size when all the THF evaporated within 24 h. The micelles formed by the block copolymers were found to be kinetically unstable (not frozen); i.e., they tended to revert to individual copolymer chains on dilution. The hydrodynamic radii, R(h), of the micelles varied with the degree of polymerization (DP) of the hydrophobic P(MA-POSS); for example, for PEG(5K)-b-P(MA-POSS), an increase from R(h) approximately 13.3 +/- 1.1 nm to R(h) approximately 17.5 +/- 1.4 nm was observed with a nominal change in the DP of P(MA-POSS) from 4 to 6. The micelles formed by the triblock copolymers (P(MA-POSS)-b-PEG(10K)-b-P(MA-POSS)) were comparable in size to the diblock copolymer micelles; e.g., R(h) approximately 14.0 +/- 1.3 nm was found for P(MA-POSS)(4)-b-PEG(10K)-b-P(MA-POSS)(4). The micellar structures created by the triblocks in aqueous media were "flowerlike", where the PEG middle block adopted a loop conformation in the micelle corona. In addition to micelles, larger aggregates formed by P(MA-POSS)-b-PEG(10K)-b-P(MA-POSS) were also detected in solution. The larger aggregates may suggest a contribution from some PEG blocks adopting an extended conformation with one end dangling in solution, causing gelation at higher copolymer concentrations via intermicellar interactions. The P(MA-POSS)(4)-b-PEG(10K)-b- P(MA-POSS)(4) formed a gel in water at approximately 8.8 wt % copolymer concentration. No gel formation by diblock copolymers was observed; however, the addition of a small amount of triblock copolymer to an aqueous solution of diblock copolymer results in gel formation. Finally, rheological behavior of the obtained gels was also investigated.

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“…Thus, ABA‐type triblock copolymers are more effective at stabilizing complex suspensions than AB‐type diblock and graft copolymers . Triblock copolymers are also known to prevent POSS aggregation caused by increases in the POSS ratio in materials and can feature selected properties as required …”

Section: Introductionmentioning

confidence: 99%

Synthesis and gas permeability of ABA-type triblock copolymers derived from fluorine-containing polyimide with polyhedral oligomeric silsesquioxane

et al. 2015

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ABA‐type triblock copolymers derived from 4,4'‐(hexafluoroisopropylidene)diphthalicanhydride‐2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (6FDA‐TeMPD) and methacryl phenyl polyhedral oligomeric silsesquioxane (MPPOSS) were synthesized by atom transfer radical polymerization. The chemical structure of the synthesized ABA‐type triblock copolymer was confirmed by 1H NMR, 13C NMR, 29Si NMR and Fourier transform infrared analyses. The ratios of 6FDA‐TeMPD and MPPOSS determined by TGA were 94/6, 85/15, 77/23, 68/32, 57/43 and 31/69. The film density of the ABA‐type triblock copolymer films did not conform to the mixing rule because of polyimide (PI) chain aggregation. Based on contact angle and water uptake analyses, the hydrophobicity of the ABA‐type triblock copolymer film was determined to be higher than the theoretical value because of POSS cage effects and PI chain aggregation. The gas permeability coefficient of the ABA‐type triblock copolymer decreased compared with that of PI because of aggregation of PI chains and inhibition of solubility decreases by substitutes with high affinity. ABA‐type triblock copolymer CO2/H2 separation performance increased compared with that of PI. The ABA‐type triblock copolymer derived from PI and MPPOSS can be described as a polymer material with higher hydrophobicity and higher CO2/H2 selectivity than PI. © 2015 Society of Chemical Industry

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Synthesis and characterization of poly(methyl methacrylate) using monofunctional polyhedral oligomeric silsesquioxane as an initiator

Cited by 30 publications

References 33 publications

Polystyrene‐block‐poly(methyl methacrylate): Initiation Issues with Block Copolymer Formation Using ARGET ATRP

Polystyrene‐block‐poly(methyl methacrylate): Initiation Issues with Block Copolymer Formation Using ARGET ATRP

Micelle Formation and Gelation of (PEG−P(MA-POSS)) Amphiphilic Block Copolymers via Associative Hydrophobic Effects

Synthesis and gas permeability of ABA-type triblock copolymers derived from fluorine-containing polyimide with polyhedral oligomeric silsesquioxane

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