Dynamic mechanical properties morphology

The miscibility of olefin copolymers such as ethylene-a-olefin copolymers was found to be controlled by the structural composition and the primary strucmre of the copolymers. Using these copolymers, binary blends with various compatibilities were prepared and the effects of compatibihty on mechanical properties in the binary blends were investigated. The tensile properties in binary blends of iPP with rubbery olefin copolymers are considerably influenced by the miscibility between iPP and the copolymers. The miscibility of iPP with other polyolefins is described in detail based on the dynamic mechanical properties, morphology observation, and solidification process. It is found that EBR, EHR, and EOR having more than 50 mol% of a-olefin are miscible with iPP in the molten state. In the solid state, the miscible copolymers are dissolved in the amorphous region of iPP, although the copolymers are excluded from crystalhne lattice of iPP. The isotactic propylene sequence in the EP copolymers with a propylene-unit content of more than 84 mol% participates in the crystallization process of iPP, resulting that a part of the EP copolymers is included in the crystalline lattice of iPP. 

Tian, D., Blacher, S., Ph Dubois and Jerome, R. (1998) Biodegradable and biocompatible inorganic-organic hybrid materials - 2. Dynamic mechanical properties, structure and morphology. Polymer, 39, 855-864. 

Ma, X., Sauer, J. A., and Hara, M. (1995). Poly(methyl methacrylate) based ionomers. 1. dynamic mechanical properties and morphology. Macromolecules 28, 3953-3962. 

Dynamic mechanical properties were measured on some PS/PMMA blends, using a Rheovibron model DDV-II system previously described (13). These measurements are a sensitive indicator of phase separation and can be used to obtain semiquantitative information about phase morphology as well (14). 

The stereoregularity—i.e., distribution of the stereosequence length in these polymers—has a marked effect on the crystallization rates and the morphology of the crystalline aggregates. These differences, in turn, influence the dynamic mechanical properties and the temperature dependence of the dynamic mechanical properties. In order to interpret any differences in the dynamic mechanical properties of polymers and copolymers of propylene oxide made with different catalysts, it was interesting to study the differences in the stereosequence length in the propylene oxide polymers made with a few representative catalysts. 

Dynamic mechanical property (DMP) measurements are used to evaluate the suitability of a polymer for a particular use in sound and vibration damping. Since the dynamic mechanical properties of a polyurethane are known to be affected by polymer morphology (4), it is important to establish the crystallization and melting behavior as well as the glass transition temperature of each polymer. Differential scanning calorimetry (DSC) was used to determine these properties and the data used to interpret the dynamic mechanical property results. 

A more selective approach consists in trying to influence the kinetics of formation of at least one network in this case, the two networks are formed more or less simultaneously, and the resulting morphology and properties can be expected to vary to some extent without changing the overall composition. The same system as previously studied, PUR/PAc, has been utilized in order to prepare a series of in situ simultaneous IPNs (SIM IPNs), by acting essentially on two synthesis parameters the temperature of the reaction medium and the amount of the polyurethane catalyst. Note that the term simultaneous refers to the onset of the reactions and not necessarily to the process. The kinetics of the two reactions are followed by Fourier transform infra-red (FTIR) spectroscopy as described earlier (7,8). In this contribution, the dynamic mechanical properties, especially the loss tangent behavior, have been examined with the aim to correlate the preceding synthesis parameters to the shape and temperature of the transitions of the IPNs. 

This chapter discusses the dynamic mechanical properties of polystyrene, styrene copolymers, rubber-modified polystyrene and rubber-modified styrene copolymers. In polystyrene, the experimental relaxation spectrum and its probable molecular origins are reviewed further the effects on the relaxations caused by polymer structure (e.g. tacticity, molecular weight, substituents and crosslinking) and additives (e.g. plasticizers, antioxidants, UV stabilizers, flame retardants and colorants) are assessed. The main relaxation behaviour of styrene copolymers is presented and some of the effects of random copolymerization on secondary mechanical relaxation processes are illustrated on styrene-co-acrylonitrile and styrene-co-methacrylic acid. Finally, in rubber-modified polystyrene and styrene copolymers, it is shown how dynamic mechanical spectroscopy can help in the characterization of rubber phase morphology through the analysis of its main relaxation loss peak. 

Mijovic, J. Tsay, L.L. Correlations between dynamic mechanical properties and nodular morphology of cured epoxy resins. Polymer... 

A polyurethane (PU)/poly(n-butyl methacrylate) (PBMA) system has been selected for an investigation of the process of phase separation in immiscible polymer mixtures. Within this system, studies are made of the XX, lx, xl, and the 11 forms. In recognition of the incompatibility of PBMA with even the oligomeric soft segment precursor of the PU, no attempt was made to equalize the rates of formation of the component linear and network polymers. Rather, a slow PU formation process is conducted at room temperature in the presence of the PBMA precursors. At suitable times, a relatively rapid photopolymerization of the PBMA precursors is carried out in the medium of the slowly polymerizing PU. The expected result is a series of polymer mixtures essentially identical in component composition and differing experimentally only in the time between the onset of PU formation and the photoinitiation of the acrylic. This report focuses on the dynamic mechanical properties cf these materials and the morphologies seen by electron microscopy. 

It is well known that the third components, although small in quantity, might also bring about other significant changes such as changes in crystalline behavior, morphology, and dynamic mechanical properties, which influence the blend properties for end use. Table III lists the data obtained by DSC for iPS-fc-iPP-iPS-iPP ternary blends. The results indicate that PP crystallization... 

Enhanced interphase interactions, deduced from thermal and dynamic mechanical properties and morphology observed by SEM, demonstrate the efficient compatibilizing effect of iPS-fo-iPP copolymer on iPS-iPP blends. Each sequence of the iPS-fc-iPP diblock copolymer can probably penetrate or easily anchor its homopolymer phase and provide important entanglements, improving the miscibility and interaction between the iPS and iPP phases. This is in good agreement with what is inferred from the mechanical properties of the iPS-fo-iPP-iPS-iPP polyblends. 

T. Hayashi, J. Ito, K. Mitani and Y. Mizutani, Dynamic mechanical properties and morphology of styrene-divinylbenzene copolymer/poly(vinyl chloride) systems, J. Appl. Polym. Sci., 1983, 28, 2867-2880. 

We begin in Section 9.2 with the morphology in binary blends of iPP and various rubbery olefin copolymers where we remark the interrelation between the miscibility and dynamic mechanical properties. Section 9.3 describes the molecular orientation behavior under tensile deformation of iPP-based blends, and we compare the differences in deformation behavior between miscible and immiscible blends. Section 9.4 contains the solidification process in iPP-based blends where the effects of miscibility in the molten state on the crystallization of iPP matrix are discussed. 

Recently, a new technology that manipulates the propylene sequence in EP copolymers has been proposed using a Cr(acac)3/MgCl2-Et2AlCl-ethylbenzoate catalyst system (36). The novel EP random copolymers with high isotacticity in propylene sequence show essentially different properties from those of conventional EPRs (36). This section deals with morphology and dynamic mechanical properties in binary blends of the novel EP copolymers (referred as EP) with various propylene contents. 

In this part, the effect of crystallization temperature on the morphology is discussed by means of the dynamic mechanical properties (24,64) that are important informations on the characterization of injection-molded products as described in Section 9.4.2 (65). 

Landry CJT, Coltrain BK, Brady BK. In situ polymerization of tetraethoxysilane in poly (methyl methacrylate) Morphology and dynamic mechanical properties. Polymer. 1992 33(7) 1486-1495. 

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