Reduction of the elongation at break of thermoplastic polyolefins through melt blending with polylactide and the influence of the amount of compatibilizers and the viscosity ratios of the blend components on phase morphology and mechanics

The objective of this work is the synthesis of a polypropylene/ethylene‐propylene‐rubber (TPO)/polylactide (PLA)/compatibilizer (PVM) blend to reduce the elongation at break of TPO by blending TPO with brittle PLA. Three TPO types with different viscosities were melt blended with PLA and an ethylene/n‐butylacrylate/glycidyl methacrylate terpolymer (PVM) as reactive compatibilizer. All blends had a constant PLA amount of 30 wt%. Two parameters were varied in the experiments, viscosity of the TPO types, and amount of PVM used in the blends. Both parameters played important roles in reducing the nominal elongation at break compared to pure TPO foils and influencing the phase morphology of extruded blend foils. The nominal elongation at break could be reduced by 100‐150% through blending TPO with PLA and PVM. Characterization regarding the blend morphology, especially the size and shape of the dispersed PLA phase in the TPO matrix was done by Environmental Scanning Electron Microscopy (ESEM) images. Investigations of the morphology showed that size and shape of dispersed PLA phases are dependent on the viscosity ratios of the blend components and on the amount of compatibilizer in the blend. AFM images of the polymer blends reveal soft rubbery layers around the dispersed PLA phases. POLYM. ENG. SCI., 56:905–913, 2016. © 2016 Society of Plastics Engineers     

Impact of the coating process on the molecular structure of starch‐based barrier coatings

Molecular analysis of starch structure can be used to explain and predict changes in physical properties, such as water vapor and oxygen barrier properties in packaging materials. Solution casting is a widely used technique to create films from starch formulations. This study compared the molecular properties of these standard films with those of experimental coatings applied to paper in laboratory‐scale and pilot‐scale trials, with all three techniques using the same starch formulation. The results revealed large differences in molecular structure, i.e., cross‐linking and hydrolysis, between films and coatings. The main differences were due to the shorter drying time allowed to laboratory‐scale coatings and the accelerated drying process in pilot trials owing to the high energy output of infrared dryers. Furthermore, surface morphology was highly affected by the coating technique used, with a rougher surface and many pinholes occurring in pilot‐scale coatings, giving lower water vapor permeability than laboratory‐scale coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41190.     

The effective hydrodynamic radius of single DNA-grafted colloids as measured by fast Brownian motion analysis

Optical tweezers accomplished with fast position detection enable one to carry out Brownian motion analysis of single DNA-grafted (grafting density: ∼1000 molecules per particle, molecular weight: 4000 bp) colloids in media of varying NaCl concentration. By that the effective hydrodynamic radius of the colloid under study is determined and found to be strongly dependent on the conformation of the grafted DNA chains. Our results compare well both with recent measurements of the pair interaction potential between DNA-grafted colloids (Kegler et al. Phys Rev Lett 2008; 100:118302) and with microfluidic studies (Gutsche et al. Microfluid Nanofluid 2006; 2:381-386). The observed scaling of the brush height with the ion concentration is in full accord with the theoretical predictions by Pincus, Zhulina, Birshtein and Borisov.     

A Mixed-Mode Analogue and Switch Level Simulator

This paper describes an experimental mixed-mode simulation system which couples an incremental time analogue simulator to an event-driven switch level simulator. the analogue timing programme uses a variable-step-size, multi-order (VSMO) numerical integration algorithm which detects and uses latency while maintaining wave-form synchronization. the switch level programme uses piecewise linear wave-forms rather than discrete states to model the operation of logical networks. A unified format in which time responses are events is used for communication between the two programmes. the mixed-mode simulator operates without backtracking or translation between logical states and analogue wave-forms.     

The Objective Conception of Context and Its Logic

In this paper, an objective conception of contexts based loosely upon situation theory is developed and formalized. Unlike subjective conceptions, which take contexts to be something like sets of beliefs, contexts on the objective conception are taken to be complex, structured pieces of the world that (in general) contain individuals, other contexts, and propositions about them. An extended first-order language for this account is developed. The language contains complex terms for propositions, and the standard predicate ist that expresses the relation that holds between a context and a proposition just in case the latter is true in the former. The logic for the objective conception features a global classical predicate calculus, a local logic for reasoning within contexts, and axioms for propositions. The specter of paradox is banished from the logic by allowing ist to be nonbivalent in problematic cases: it is not in general the case, for any context c and proposition p, that either ist(c,p) or ist(c, ¬ p). An important representational capability of the logic is illustrated by proving an appropriately modified version of an illustrative theorem from McCarthy's classic Blocks World example.     

Relations between material, intermediate and spatial generalized strain measures for anisotropic multiplicative inelasticity

Summary In this contribution we discuss the application of generalized strain measures to finite inelasticity based on the multiplicative decomposition of the total deformation gradient. The underlying symmetry properties of the material are modelled via the incorporation of structural tensors while the evolution of any inelastic spin is neglected. Appropriate pushforward and pullback transformations of particular generalized strain measures to different configurations enable the setup of anisotropic hyperelastic formats with respect to all configurations of interest. This rather general formalism turns out be convenient in view of for instance efficient numerical algorithms and computational applications.     

Probleme des abbaus an folienbildenden thermoplastischen hochpolymeren

The mass-produced thermoplastics, PVC, polystyrene and polyolefins, have increasingly gained ground in fields of application where, during and after use, they are subjected as thin layers, e.g. in the form of films, to normal environmental influences. Degradation reactions on thin layers caused by heat and light in the presence of oxygen are gaining importance as much as a “controlled autoxidation” might open up new fields of application. Initiation and acceleration of autoxidation by ?potential sensitizers”? in the presence of oxygen and beams of light are critically evaluated with a view towards desired degradability.     

Dose equivalent measurements in a strongly pulsed high-energy radiation field

The stray radiation field outside the shielding of high-energy accelerators comprises neutrons, photons and charged particles with a wide range of energies. Often, accelerators operate by accelerating and ejecting short pulses of particles, creating an analogue, pulsed radiation field. The pulses can be as short as 10 micros with high instantaneous fluence rates and dose rates. Measurements of average dose equivalent (rate) for radiation protection purposes in these fields present a challenge for instrumentation. The performance of three instruments (i.e. a recombination chamber, the Sievert Instrument and a HANDI-TEPC) measuring total dose equivalent is compared in a high-energy reference radiation field (CERF) and a strongly pulsed, high-energy radiation field at the CERN proton synchrotron (PS).     

Oberflächenwellen‐Strukturen in Cu‐Damaszentechnologie

Application of the Copper Damascene Technology to Surface Acoustic Wave Structures A novel fabrication technology for power SAW devices with embedded interdigital transducers of a copper thin film system (copper damascene technology) is described. Such SAW structures have a significantly higher power durability and lifetime compared to usual Al‐based transducers. These properties denote that they become attractive for new applications where high SAW amplitudes and a flat surface of the device are required for these applications.