Flexibilität und thermodynamisches Verhalten von isotaktischem und syndiotaktischem Polymethylmethacrylat

Schulz, Von G. V.; Wunderlich, Winfried; Kirste, R. G.

doi:10.1002/macp.1964.020750103

Cited by 47 publications

(12 citation statements)

References 33 publications

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“…Comparison with Other Models. Wu11,15 has offered an expression for the calculation of the plateau modulus which is Gl, = O.SSSpkTN^m^Cj2 (35) The premise upon which this expression is based, namely, that Me cc CJ is incorrect since contour length density is ignored and the experimental observations that C, can of GÑ.c From nearly free rotating Figure 3. Gj, (298 K) as a function of Ke2p3 from the data of increase, remains constant or decreases with increasing temperature, while Me only becomes larger with an increase in temperature.…”

Section: Resultsmentioning

confidence: 99%

Connection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic Properties

Fetters¹,

Lohse²,

Richter³

et al. 1994

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One of the main goals of polymer science has been to relate the structure of macromolecular chains to their macroscopic properties. In particular, it has been hoped that one could relate the sizes of polymer coils to the degree to which they entangle with one another and thus to their viscoelasticity in the melt. In recent years, the availability of model polymers with nearly monodisperse molecular weight distributions and precisely controlled chemical structures has allowed for improved data both on rheology and on the dimensions of the chains. This has now allowed us to determine the correlations between such properties as chain dimensions, density, and plateau modulus and to show that some quite simple relations exist between them. The main body of these data is on polymers that can be considered to be models for polyolefins. These have been made by the hydrogenation of polydienes synthesized by anionic polymerization techniques. In this way the molecular weight distribution can be made to be nearly monodisperse (Afw/M" < 1.1) and the chemical structure is well controlled. For example, models of a wide range of ethylene-butene copolymers have been made by the saturation of polybutadienes with a range of vinyl content. Such polymers can be made at many molecular weights as well. The viscoelastic properties of these polymers have been measured very precisely, and their chain dimensions have been determined by small-angle neutron scattering. To a high degree of correlation, we find that the mean-square unperturbed end-to-end distance,

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Section: Resultsmentioning

confidence: 99%

Connection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic Properties

Fetters¹,

Lohse²,

Richter³

et al. 1994

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“…23,24 Syndiotactic PMMA/n-butyl Chloride System (s-PMMA/nBuCl) temperature for s-PMMA in n-butyl chloride was reported as 35.0°C by static light experiments. 40 Stereoregular poly(methyl methacrylate)s, (s-PMMA)s have a strong tendency to form the ordered aggregated structures in solution. [41][42][43][44][45] In addition to aggregates of the socalled stereocomplex of PMMA which arise on mixing solutions of isotactic and syndiotactic (PMMA)s, attention has been devoted in recent years to the self-aggregation of s-PMMA alone, using NMR and infrared spectroscopy.…”

Section: Atactic Pmma/n-butyl Chloride Systemmentioning

confidence: 99%

Dynamic light scattering studies of atactic and syndiotactic poly(methyl methacrylate)s in dilute theta solution

Gürel

Kayaman

Baysal

et al. 1999

J. Polym. Sci. B Polym. Phys.

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“…[13] The phase-separation temperature, T p , of the studied sample was, however, determined to be 20.85 AE 0.25 8C at a concentration of 1.12 10 À4 g mL…”

Section: Resultsmentioning

confidence: 99%

Light‐Scattering Study of the Aggregation of Syndiotactic Poly(methyl methacrylate) in Solution

et al. 2004

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Syndiotactic poly(methyl methacrylate (s-PMMA) may undergo aggregation in n-butyl chloride (n-BuCl) at temperatures below the theta temperature. The aggregation behavior of the s-PMMA with weight-average molecular weight M(w) =6.06 x 10(5) g mol(-1) was studied by a combination of static and dynamic laser-light-scattering experiments. A solution of concentration 1.12 x 10(-4) g mL(-1) was quenched from 50 degrees C (above the theta temperature in n-BuCl, 35 degrees C to 12 degrees C, and the aggregation process was measured over 60 h. The time dependence of M(w) the root-mean-square z-average radius of gyration < R(g) >, and the average hydrodynamic radius were used to monitor the growth of the aggregates, with the result M(w) approximately < R(g) > d(f) (where d(f) = 1.98 +/- 0.02), which implies the formation of a fractal aggregate. The observed fractal dimension, d(f), is close to that expected for a reaction-limited cluster aggregation for which d(f) = 2.1. In addition, atomic force microscopy was used to image the aggregates.

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Flexibilität und thermodynamisches Verhalten von isotaktischem und syndiotaktischem Polymethylmethacrylat

Cited by 47 publications

References 33 publications

Connection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic Properties

Connection between Polymer Molecular Weight, Density, Chain Dimensions, and Melt Viscoelastic Properties

Dynamic light scattering studies of atactic and syndiotactic poly(methyl methacrylate)s in dilute theta solution

Light‐Scattering Study of the Aggregation of Syndiotactic Poly(methyl methacrylate) in Solution

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