Micro and Nano Structuring as Method to Enhance the Functional Properties of Starch-Based Polymeric Materials

The use of starch, the second most abundant natural resource in the word, as polymer is unprofitable and limited by certain functional properties. The structuring of multiphase polymeric materials represents the process of diminishing the dispersed phases till micro-and/or nano-dimensions and the positioning of the resulted fields in an order through which the properties of interest are achieved as far as possible. The structuring is reached by controlling the interface properties for achieving physical, chemical, biological or rheological compatibilization, mainly by melt compounding procedure. The chapter proves that the structuring of starch-based multiphases polymeric systems by reactive compatibilization is a good possibility to guarantee the functional properties, required by sustainable applications, of interest even in 2050 perspective. The chapter underlines also that the structuring by reactive compatibilization is connected with the formulation designing and choosing of the melt-compounding conditions in such a manner for the chemical bonding of the minority phases with the main polymeric matrix and therefore increasing the component miscibility and the functional properties of the resulted materials till the requirements of the sustainable applications

The Dependence of the XRD Morphology of Some Bionanocomposites on the Silicate Treatment

The degree of intercalation of the polyvinyl alcohol-starch blend with the layered silicate is increased if the silicates is untreated or intercalated with ammonium ions that contain small radicals. If untreated silicate like NaMMT is used, it is possible to obtain exfoliated-intercalated nanocomposites. The materials based on PVOH, starch, and Nanocor I 28, Nanocor I 33, or Cloisite 15 A can be intercalated nanocomposites. If the blend of PVOH and starch is reinforced with Cloisite 93 A, microcomposites can result. The study will continue with the analysis of the new morphologies considering the transmission electron microscopy (TEM)

New Evidences on the Process Sensitivity of Some Renewable Blends Based on Starch considering Their Melt Rheological Properties

The degradability and processability of new renewable materials based on starch and PVOH were studied using the melt flow index (MFI) method by measuring the melt rheological properties which depend not only on the extrusion conditions and material formulation but also on the macromolecule characteristics which can be modified by chemical degradation. These results were correlated with other material properties like color and cross-linking degree. The obtained results show that flowing in the melted state of the studied materials is accompanied by a second process of chains chemical degradation. It was observed that, at the same level of additivation, under identical extrusion conditions, the melted blends with corn starch as main component are highly mechanically sensitive and degrade mostly by chains scission and those with PVOH as major component are highly temperature sensitive and degrade mainly by cross-linking. The obtained results show also that each PVOH-starch blend requires particular formulation and individual windows of melt processing conditions. These results are a good proof that the MFI method is a good path to study the degradability and moldability of process sensitive polymeric materials like those based on starch and PVOH

Controlling the Melt Resistance to Flow as a Possibility of Improving the Miscibility and the Time Behavior of Some Blends Based on Starch

The paper proves that the miscibility of some blends based on starch can be improved by finding for each of them the melt resistance to flow at which the nonstationary flow and the melt degradation are avoided and the developed shear rate homogenizes optimally the material composition. The obtained results show that, for process sensitive materials like starches, the border between good and less miscibility is so narrow that the window of melt processing conditions and the best formulation must be found for each of them. The improving of miscibility by controlling the melt resistance to flow proves to be a good method to prevent retrogradation and plasticizer leaching and so to handle the new compounds behavior during usage

The Shape Memory Polymeric Materials and the Additive Manufacturing Technology as Promoter of the Future Smart Society

Humans have progressed from the Stone Age, through the Bronze, Iron, and Steel Ages, into its [...

Embedded Target Filler and Natural Fibres as Interface Agents in Controlling the Stretchability of New Starch and PVOH-Based Materials for Rethinked Sustainable Packaging

A structuring solution converting starch into a multiphase polymeric material was obtained through a melt compounding sequence, which can be irreversibly shaped by thermoforming into rethinked, sustainable packaging, based on the physical modification of starch with polyvinyl alcohol (PVOH), target fillers, (CaCO3 and wood flour), and a good plasticizer compatible with the polar components. Polymeric material can be thermoformed if it can be stretched without breaking in the positive temperature range, have functional properties required by the application, and keep its shape and properties after stretching for more than six months. The properties of the selected quaternary starch-based compound, fulfil the requirements for a thermoformable polymeric material due to the chemical compatibility between the components and the compounding in a selected procedure and optimal conditions wich ensure a comfortable miscibility. Most likely, the obtained miscibility can be explained only by the arrangement of the wood flour at the interface, where it acts as compatibilizer with a main role in structuring the new starch-based materials. The compatibilizer role of the wood flour was proved for the quaternary selected blend by the changing of the thermal degradation mechanism, from one with two stages for binary and tertiary blends, to one consisting of a single stage: decreasing till elimination of morphological defects, the reproducibility of the mechanical properties, stretching without breaking, and dimensional stability after stretching. Future studies will aim to achieve rethinked packaging for applications that require higher strength properties

Estimating the 3D Printing Defects by Micro-Computed Tomography

Micro-computed tomography (µ-CT) is an X-ray technique with (sub)micron resolution, [...