X‐Ray Scattering Studies on Multiphasic Polymer Systems

Abstract

At present, multiphase and multicomponent materials such as polymer alloys, blends, and composites consume over 80 wt% of all commercially-produced resins. The increase of this particular segment of the plastics industry is about three times faster than of the industry as a whole. The reason is that the modification by blending may improve significantly the resins' mechanical performance and processability, being at the same time cost effective. Those few resins that are used without adding of other components are most frequently semicrystalline, i.e. they already have a multiphase structure that makes other modification less urgent [1].Recently, a large window has opened for new structural applications of the multicomponent polymer systems with the advent of nanoscale filled polymer composites. Changing the type, size, shape, volume fraction, interface, and degree of dispersion or aggregation of the nanofillers enables a great amount of unique combinations of properties with high potential for successful commercial development [2].In technical literature the terms 'phase' and 'component' are often used interchangeably.In thermodynamics, however, a clear distinction is made. Thus, a phase is defined as a chemically and physically uniform quantity of matter that can be separated mechanically from a nonhomogeneous mixture. Hence, multiphasic polymer systems would comprise at least two different phases, e.g. semicrystalline single polymers featuring amorphous and crystalline phases or polymorphic polymers containing different concomitant crystalline phases. Many polymer systems with industrial importance such as blends, colloidal polymers, polymer composites/ filled polymers, etc. comprise two or more chemically distinct components, each one of them being able to contain various phases as well. These components may have different sizes, with microscopic to nanoscopic blocks being present.

Toward a Tunable Fibrous Scaffold: Structural Development during Uniaxial Drawing of Coextruded Poly(ε-caprolactone) Fibers

“…The first was the evolution of a minor 001 reflection during uniaxial drawing, which becomes a prominent reflection after the quenching process. While the previous analysis of hk 0 reflections (Figure ) revealed a high degree of interchain crystal orientation (Figure ), the appearance of an 001 reflection, such as that observed in Figure a, suggests that there also exists a strong intrachain alignment developed during the uniaxial drawing process . Further examination of the integrated 1D WAXS integrations in Figure a revealed that both the 110 and 200 peaks were broadened.…”

“…While the previous analysis of hk0 reflections (Figure 3) revealed a high degree of interchain crystal orientation (Figure 3), the appearance of an 001 reflection, such as that observed in Figure 6a, suggests that there also exists a strong intrachain alignment developed during the uniaxial drawing process. 58 Further examination of the integrated 1D WAXS integrations in Figure 6a revealed that both the 110 and 200 peaks were broadened. This broadening of the WAXS reflections indicates a decrease of the orthogonal size of individual crystallites with respect to the 110 and 200 crystallographic planes and can be quantified using the Scherrer formula (eq 4).…”

Light and Shape‐Memory Polymers: Characterization, Preparation, Stimulation, and Application

“…The scattered X-rays are collected by a detector, forming scattering patterns. [77,78] The diffraction or interference of reflected light can be defined using the Bragg equation:…”

“…The scattered X‐rays are collected by a detector, forming scattering patterns. [ 77,78 ] The diffraction or interference of reflected light can be defined using the Bragg equation: $$$$\begin{equation}2d\;\sin \;\theta = n\lambda \end{equation}$$$$where d , n , and λ are lattice spacing, diffraction order, and peak wavelength, respectively. θ is the angle between the incident light and the normal line.…”

“…These include: 1) Wide‐angle X‐ray scattering (WAXS), commonly referred to as X‐ray diffraction (XRD), which typically explores length scale in the order of molecular dimensions and the information about the arrangement of chain segments; 2) Small‐angle X‐ray scattering (SAXS), which examines long‐range ordering and detects nanostructural organizations; and 3) Ultra‐small‐angle X‐ray scattering, which provides access to structures at the micro‐scale. [ 77 ] These related measurements, thus, can obtain information on crystal sizes, orientation degrees, and internal structures.…”