A calorimetric investigation of the formation of a stereocomplex in poly(methyl methacrylate) solutions

Biroš, J.; Máša, Z.; Pouchlý, Julius

doi:10.1016/0014-3057(74)90172-4

Cited by 35 publications

(6 citation statements)

References 13 publications

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“…On the research series of polymerization mechanistic studies, we initially had difficulties in controlling and estimating polymerizations. Besides, it-PMMA and st-PMAA did not form clear 2:1 stereocomplexes on the QCM in all cases, but 1.22 ± 0.34:1 ( n = 29), implying a mixture of 2:1 and 1:1 stereocomplexes. ,, Therefore, the complex efficiency (C.E.) was determined to evaluate the polymerization value in this study as the following C.E. = ( increased weight after polymerization ) / ( extracted st-PMAA weight ) × 100 …”

Section: Resultsmentioning

confidence: 97%

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Mechanistic Studies on Template Polymerization in Porous Isotactic Poly(methyl methacrylate) Thin Films by Radical Polymerization and Postpolymerization of Methacrylate Derivatives

2009

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The postpolymerization of various vinyl monomers was applied for mechanistic studies of the template polymerization of methacrylic acid (MAA) in porous isotactic (it-) poly(methyl methacrylate) (PMMA) thin films on quartz crystal microbalance (QCM) substrates and on silica gels, which were prepared by the alternative layer-by-layer (LbL) assembly of it-PMMA/syndiotactic- (st-) poly(methacrylic acid) (PMAA). In this study, QCM analyses, FT-IR/ATR spectra, 1H NMR spectra, and SEC were employed to investigate the polymerization mechanism, and they highlighted the following points: (1) the livingness of polymer radicals by postpolymerization on a QCM, (2) substituent effects on the polymerizability in porous it-PMMA thin films, and (3) partial stereocomplex formations of polymerized MMA with host it-PMMAs. Stabilities of porous it-PMMA thin films on QCM substrates and on silica gels are also discussed herein.

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Section: Resultsmentioning

confidence: 97%

“…Besides, it-PMMA and st-PMAA did not form clear 2:1 stereocomplexes on the QCM in all cases, but 1.22 ( 0.34:1 (n ) 29), implying a mixture of 2:1 and 1:1 stereocomplexes. 15,18,38 Therefore, the complex efficiency (C.E.) was determined to evaluate the polymerization value in this study as the following…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Studies on Template Polymerization in Porous Isotactic Poly(methyl methacrylate) Thin Films by Radical Polymerization and Postpolymerization of Methacrylate Derivatives

2009

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“…For the solvent effects in blends, three groups of solvents for blending mixtures of i-PMMA and s-PMMA can be classified: complexing, weakly complexing, and noncomplexing types (56,57). Furthermore, the maximum effect of the mixing ratio on the stereocomplex formation is reported to be for mixtures with a weight ratio of (i/s) = 1/2, although other ratios of (i/s) = 2/1 and 1/1 are also reported to induce complexation (50)(51)(52)58,59). Various explanations have been proposed for the formation of stereocomplexes between i-PMMA and s-PMMA (60)(61)(62).…”

Section: Complex Formation In Mixtures Of Pmma Of Opposite Tacticitiesmentioning

confidence: 99%

Tacticity in Vinyl Polymers

Woo

Chang

2011

Encyclopedia of Polymer Science and Technology

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Various issues of tacticity in vinyl polymers are discussed. First, tacticity is defined and the concepts of tactic forms in polymers as a stereoregular configuration order are introduced, and illustration schemes for common polymer tacticity are shown. Effects of tacticity in polymer structures on crystalline morphology and property are briefly discussed. Several commercially useful tactic polymers are examined, by using examples of vinyl‐type polymers such as tactic polypropylene (PP), polystyrene (PS), and poly(methyl methacrylate) (PMMA). Catalysts and synthesis routes for producing stereoregular tactic polymers are discussed mainly using PMMA as an example. Tacticity in polymers is related to differences in microstructures, morphology, crystalline polymorphism, and physical/mechanical properties. Tactic polymers possess structural order and are to crystallize. Tacticity and crystalline properties of polymers are discussed. Crystal polymorphism in some tactic polymers, such as syndiotactic polystyrene (s‐PS), is discussed in greater detail. Complex formation in mixtures of polymers of opposite tacticities, just like mixtures of polymers of opposite chiral forms, has been reported. Complex formation in mixtures of polymers of opposite (s‐ and i‐tacticity) is discussed using examples of isotactic PMMA (i‐PMMA) and syndiotactic PMMA (s‐PMMA); on the other hand, complex formation of mixtures of other tactic polymers, such as i‐PS/s‐PS or i‐PP/s‐PP, is not known. Effects of tacticity on the miscibility and phase behavior in blends of tactic polymers with other polymers are surveyed and expounded. Blends of polymers of same chemical structure but opposite tacticities are not always miscible, as exemplified in a blend of nonpolar and highly crystalline s‐PP with i‐PP, showing immiscibility with upper critical solution temperature behavior but a‐PP being miscible with s‐PP or i‐PP. In addition, phase behaviors of binary blends of two isomeric polymers are addressed. In blends with weak interactions and borderline phase homogeneity, the tacticity effect on miscibility is usually more pronounced; in contrast, the effect on the phase behavior may be minimal in systems with strong intermolecular interactions.

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“…Others factors, such as polymer concentration, 25,29,30 mixing ratio, 2,4,8,32,33 and molecular weight 3,31,34 of the stereoregular polymers, also influence formation of stereocomplexes between iPMMA and sPMMA. For examples, the maximum effect of stereocomplex formation is reported to be for mixtures with a weight ratio of i/s ) 1/2, although other ratios of i/s ) 2/1 and 1/1 are also reported.…”

Section: Introductionmentioning

confidence: 99%

“…For examples, the maximum effect of stereocomplex formation is reported to be for mixtures with a weight ratio of i/s ) 1/2, although other ratios of i/s ) 2/1 and 1/1 are also reported. 2,4,8,32,33 The formation of a stereocomplex between iPMMA and sPMMA is more hindered for species of the high molecular weights. 3,31 On the other hand, WAXS studies indicate that the crystalline structure of the stereocomplex is made of a double-stranded helix with a 9/1 helical conformation by Schomaker et al 11 O'Reilly and Mosher 15 were the first to report the conformational energy difference of stereoregular PMMA by using IR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Effect of a Miscible Polymeric Diluent on Complex Formation between Isotactic and Syndiotactic Poly(methyl methacrylate)

Chang

Woo

2009

Ind. Eng. Chem. Res.

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Formation of a stereocomplex structure in a blend of isotactic and syndiotactic poly(methyl methacrylate)s (iPMMA/sPMMA) was found to be significantly enhanced by introducing a mutual miscible diluent of poly(ethylene oxide) (PEO) in the blend, even when prepared using a kinetically hindered noncomplexing CHCl3 solvent. Mechanisms and influencing factors, such as thermal treatment, annealing temperature, annealing time, or PEO content in blends, on structures of stereocomplexes in the ternary iPMMA/sPMMA/PEO blends are discussed. WAXD result showed that addition of PEO in the iPMMA/sPMMA blend did not alter the crystal cells in the complexes. Melting peaks associated with the complexes were analyzed for discerning possible structural mechanisms. When annealed at specific temperatures, multiple endothermic peaks of the complexes increased in intensity as PEO contents increased in the ternary blends. Analysis shows that the lower melting peak (P1) represents shorter stereocomplex sequences or stereocomplex detached from PEO or connected with partial PEO, but the higher melting peak (P3) is related to the stereocomplex physically interconnected in the presence of PEO. The PEO molecules are thought to more easily interact with the stereocomplexes in blends by acting as a plasticizer, which decreases T g of the more rigid PMMA chain segments. Physical interaction or miscibility-enhanced chain entanglement probably exists between PEO and the stereocomplex of tactic PMMAs, leading to stereocomplex formation in the iPMMA/sPMMA/PEO ternary blend. FT-IR characterization provided evidence of weak interactions between PEO and the stereocomplex of PMMA. IR peaks sensitive to complex structures with respect to temperature were analyzed for discerning effects by adding PEO. The stereocomplex formation of ternary blends with PEO is due to the weak interaction of ester groups and methoxy groups between PMMA and PEO.

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A calorimetric investigation of the formation of a stereocomplex in poly(methyl methacrylate) solutions

Cited by 35 publications

References 13 publications

Mechanistic Studies on Template Polymerization in Porous Isotactic Poly(methyl methacrylate) Thin Films by Radical Polymerization and Postpolymerization of Methacrylate Derivatives

Mechanistic Studies on Template Polymerization in Porous Isotactic Poly(methyl methacrylate) Thin Films by Radical Polymerization and Postpolymerization of Methacrylate Derivatives

Tacticity in Vinyl Polymers

Effect of a Miscible Polymeric Diluent on Complex Formation between Isotactic and Syndiotactic Poly(methyl methacrylate)

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