Applications of Modulated Temperature Differential Scanning Calorimetry to Polymer Blends and Related Systems

Abstract

IntroductionThe characterisation of multi-component polymer materials [1] has been pursued vigorously in recent years. Many types of such materials (including polymer blends, block copolymers, structured latexes and interpenetrating polymer networks) are now commercially available [2,3] and their ever better characterisation remains important. It is necessary to obtain morphological parameters such as the thickness and weight fraction of interfaces/interphases 1 and to understand the relationships between morphology and mechanical properties of such multi-component polymeric materials [2][3][4][5][6][7][8]. A common feature across the spectrum of multi-component polymeric materials is the presence of interfaces [2,5,7,8]. The properties of the interface are invariably central to the properties of the composite and the ability to understand and optimise the interface is recognised as a key feature in the development of improved polymeric materials. Most polymer pairs are immiscible [5,6]. Thus, the majority of blends are two-phase and their morphology depends on the type of molecular interaction, the rheology of the components and the processing history. Models used to describe 1 The term interface implies a two-dimensional structure. It is clear in nearly all practical cases in polymer science that the regions between phases are three-dimensional in nature. These regions are also often likely not to be isotropic, but of a compositionally graded nature which means they do not meet the strict definition of a phase. In this chapter, the terms interface and interphase will be used essentially interchangeably.

A DSC and XPS characterization of core–shell morphology of block copolymer nanoparticles

“…For the PS block itself, only 24% forms a bulk core phase while 76% is entrapped in the interface. In addition, the fact that the glass transitions are shifted compared to pure polymers are indicative that the two separated phases are not pure [27][28][29][30][31][32]. The glass transitions of PHEA shell is found at…”

“…Originally reported by Tembu-Nzudie et al in 1994 for poly(butadiene)/poly(methyl methacrylate) latex [26], the method was further elaborated [24]. In particular, the groups of Hourston [27,28], Karlsson [29,30], and Sunberg [31,32] have emphasized the interest of DSC or modulated temperature DSC for determining the interfacial content of composite latex.…”

“…4b shows dC p /dT, vs. temperature. Hourston et al have highlighted the utility of treating DSC data in the form of temperature differential of the heat capacity as a function of temperature [27,28]. Accordingly, the lyophilized copolymer sample (trace 1) displays now two single and well-defined peaks at 28.1°C and 85.5°C, which can be assigned respectively to a shell phase rich in PHEA and a core phase rich in PS.…”

Starch / Polyvinyl Alcohol Blends Containing Polyurethane as Plasticizer

“…It is used to investigate the effect of blending starch, PVA and PU on the glass transitions. The use of modulated DSC allows separating the total heat flow into reversing and nonreversing components and the differential of heat capacity signal with temperature, dC p /dT, over the glass transition region, makes easier the T g determination [35].…”