Plastic Compatibility Research Articles

Poly(vinyl chloride) plasticates modified by polystyrene: features of preparation, morphology and properties

The influence of component composition and the nature of plasticizer on the features of intermolecular interactions in the system poly(vinyl chloride)–polystyrene–diester phthalate was established. It was found that polystyrene macromolecules are actively involved in interactions with both poly(vinyl chloride) macromolecules and plasticizer molecules, forming associates of slightly smaller size. It was noted that the wetting angle of the surface by plasticizer and the work of adhesion largely depend on the nature of a plasticizer and a polymer dissolved in it. This indicates a significant effect of the nature and content of the polymer modifier on the compatibility of poly(vinyl chloride) and plasticizer and changes in thermodynamic characteristics of the system. The influence of the nature and content of polystyrene modifier on physicochemical features of the migration process of diester phthalate plasticizer from modified poly(vinyl chloride) plasticate as well as on its morphological features was studied. It was found that the thermodynamic compatibility of the components is significantly affected by the wettability of the surface of fine polymer particles with liquid plasticizers, which, in turn, affects the release (migration) of the plasticizer from poly(vinyl chloride) plastics during operation of products based on them. Pre-dissolution of suspension polystyrene or acrylonitrile butadiene styrene plastic in the plasticizer, regardless of its nature, leads to a significant reduction in the value of migration.

Evaluation of the compatibility of waste plastics and bitumen using micromechanical modeling

Introducing waste plastics in bituminous composites can increase the composites’ durability, provided that the waste plastics are compatibilized with bitumen to avoid phase separation. To enhance the compatibility of plastic particles with bitumen, various treatment methods were used to alter their physical and chemical characteristics. Considering the complex nature of bitumen, knowing the properties of isolated particles is not sufficient to indicate their performance in a bituminous composite. Therefore, there is a need to quantify the efficacy of each treatment method directly. While the plastic-bitumen interface can be examined via advanced characterization instruments such as atomic force microscopy, those methods are often relatively complicated and time consuming for formulators and designers. Here, we use a heterogeneous micromechanical model to calculate compatibility indicators; the model is tailored for viscoelastic bituminous composites containing waste-plastic particles. With experiments using a dynamic shear rheometer and a bending beam rheometer, data were generated on the bitumen with and without waste plastics having various surface treatments. The model was then used to calculate the Effective Volume Filling (EVF) ratio to indicate the interaction between plastics and bitumen as a measure of compatibility. A higher EVF ratio indicates greater compatibility. The corresponding EVF ratio was found to be higher for the oil-treated plastics compared to non-treated plastics, demonstrating higher compatibility of the oil-treated plastics with bitumen. This study promotes sustainability in construction by facilitating the use of waste plastics and enhancing the cracking resistance of bitumen.

Unraveling dislocation mediated plasticity and strengthening in crack-resistant ZnAlMg coatings

Mg-alloyed zinc coatings suffer from early cracking during deformation due to the combined influences of detrimental constituents (e.g., Zn/MgZn2 binary eutectic), unfavorable crystal orientations and incompatible local plastic deformation. This study addresses the crack resistance and deformation mechanisms of a ZnAlMg coating, in the absence of binary eutectic, by using correlative in-situ scanning electron microscopy tensile tests, electron backscatter diffraction, scanning transmission electron microscopy and micro digital image correlation methods. The plasticity and strengthening mechanisms of the binary eutectic-free ZnAlMg coating are thoroughly unravelled via theoretical and experimental approaches including dislocation slip trace analysis, Taylor factor calculations, quantitative dislocation density determination and slip/strain transfer across the grain boundaries. It has been found that the microstructure of the coating, comprising of primary zinc and ternary eutectic, effectively accommodates the applied strain without cracking till fracture of steel substrate. The absence of binary eutectic and the activation of abundant deformation mechanisms in the coating microstructure, promote local compatible plastic deformation and inhibit early damage. Effective slip transfer is unveiled by activation of pyramidal <c+a> slip in addition to primary dislocation slip systems. The present findings deliver significant insights and solution for improvement in the formability of Mg-alloyed zinc coatings on steel sheets by tailoring the microstructure.

Molecular Dynamics Simulation of the Influence of PEG‐TDI Aging Degradation on Diffusibility and Compatibility of NG and BTTN

AbstractIn this study, the molecular dynamics method was used to explore the effects of the degradation of an adhesion agent (PEG‐TDI) in a nitrate ester plasticized polyether propellant on the compatibility and diffusibility of energetic plasticizers (NG and BTTN) and the glass transition temperature and mechanical properties of the blend system (PEG‐TDI/NG/BTTN). The radial distribution function, the mean square radius of gyration, and fractional free volume of the PEG‐TDI/NG/BTTN system under different degrees of degradation conditions were calculated. The diffusibility and compatibility of NG and BTTN, the glass transition temperature, and the mechanical properties of the blended system were then discussed. The results showed that, with aggravation of the degree of PEG‐TDI degradation, the fractional free volume in the system decreased, intermolecular hydrogen bonding and van der Waals interactions enhanced, and the size of the polymeric nematic decreased. These changes eventually caused the diffusion ability of NG and BTTN to weaken, compatibility to be enhanced, and glass transition temperature, stiffness, and yield strength of the PEG‐TDI/NG/BTTN system to increase.

Plasticity enhancement mechanism of DP600 steel sheets during uniaxial quasi-static/dynamic forming

The main goals of this work are to explore the macro- and micro- mechanisms of plasticity enhancement of DP600 steel sheets during the hybrid uniaxial tension consisting of quasi-static forming and then dynamic electrohydraulic forming (EHF). The experimental results showed that the room-temperature plasticity of DP600 sheets during the hybrid forming process was improved significantly: the limit strain was improved by 35 %, and the total percentage elongation was improved by 25 % in contrast to that during the quasi-static forming process. Then, the mechanical behavior, fractography and microstructure evolution of the specimens were analyzed. The quasi-static pre-deformation led to the change of the material constitutive of DP600 steel at high strain rate, improved the formability in the subsequent dynamic step and resulted in an excellent final plasticity. The inertial effect in the dynamic EHF process and the additional stress increment Δσθ caused by quasi-static pre-deformation reduced the velocity gradient of the mass particles along the tensile direction after starting plastic instability, thereby coordinating the subsequent deformation and enhancing the final plasticity of the hybrid uniaxial tension specimens. Under high strain rate, the nucleation from the existing dislocations caused higher dislocation density in the ferrite phase, which offset the easy stacking, winding, and uneven distribution of the dislocations caused by quasi-static pre-deformation. Besides, typical [0 1−1]MT deformation twins presenting in the martensite phase, enhanced the plastic compatibility of the ferrite and martensite phases and contributed to the plasticity improvement.

Influence of polymer and plasticizer compatibility on the quality indicators of bituminous binder

Influence of polymer and plasticizer compatibility on the quality indicators of bituminous binder

Lactide-derived ester oligomers for highly compatible poly(lactide) plasticizer produced through an eco-friendly process: renewable resources, biodegradation, enhanced flexibility, and elastomeric performance

Highly compatible PLA plasticizers were prepared using lactide, which demonstrated “double green” based on renewability and biodegradation, and “dual performances” including flexible and elastomeric behaviors.

Thermally Activated Jamming in Ultrasonic Powder Compaction

Herein, the role of thermal softening in ultrasonic powder compaction is assessed by comparing the densification behaviors of nominally pure Cu and a thermally stable CuTa alloy. These materials have similar thermal properties, but pure Cu softens at much lower temperatures than does the CuTa alloy. Using a specialized ultrasonic powder compaction setup, in situ measurements of relative density, sonotrode power consumption, and temperature are collected, which together provide a time‐dependent geometric hardening parameter that reflects the structure of the compact. The geometric hardening data for the pure Cu powder reveal three distinct stages of densification: an initial particle rearrangement stage; a jamming transition where strong junctions develop between particles; and a final stage characterized by compatible plastic deformation. By contrast, the geometric hardening data for the thermally stable CuTa powder show that it remains a weak fluidized granular medium, despite experiencing higher normal pressures, oscillation amplitudes, and temperatures. The contrasting behaviors of the Cu and the CuTa powders suggest that a thermally activated jamming transition drives interparticle junction growth and densification in ultrasonic powder compaction.

A two-stage sequential approach for scheduling with lot-sizing decisions in the context of plastic injection systems

This study addresses a planning problem for plastics injection systems, where final products are assembled of compatible plastic pieces. Additionally, the production of pieces requires the use of dedicated molds that are installed on compatible injection machines (leading to long setup times). Then, our Manufacturing Planning Problem determines the lot-size of each product in terms of the number of cycles for each piece–mold–machine combination and the scheduling of molds for each injection machine in a single planning period to maximize the total profit. We consider constraints for machines’ available time and avoid mold overlapping on different machines. Moreover, we define a mixed-integer linear program for our problem, and we obtain high-quality solutions for medium-size instances using a commercial solver in minutes. Still, the convergence to optimal solutions for large instances is slower. In response, we propose a two-stage sequential approach that takes advantage of the mathematical formulation to obtain better solutions for large instances in short computational times.

An energy based modeling for the acoustic softening effect on the Hall-Petch behavior of pure titanium in ultrasonic vibration assisted micro-tension

The acoustic softening effect in metals during plastic deformation has been widely investigated in the past decades. However, the mechanism of such an acoustic plasticity remains controversial. As a result, several models were proposed to understand the acoustic softening effect in terms of stress superposition, thermal activation theory, crystal plastic theory and other mechanisms associated with dislocation evolution. In this study, we proposed a mechanism that the athermal dislocation dynamics may heterogeneously change at microstructure level during ultrasonic vibration assisted (UVA) deformation. Specifically, the work required to eject dislocations from grain boundaries may be altered by the acoustic energy absorption difference of a dislocation in the grain interior and one in the grain boundary. As a result, the acoustic softening effect on the Hall-Petch behavior was modeled by incorporating a power function of acoustic energy density into the dislocation ejection work. To validate the developed model, UVA micro-tension tests were conducted on pure titanium specimens. Results showed that the Hall-Petch slope decreased due to ultrasonic vibration, and the ultrasound-induced decrease of the Hall-Petch slope increased with plastic deformation. Note that our model predictions matched well with the experimental results at the lower strains, providing an alternative insight into the acoustic softening effect on the Hall-Petch behavior. Microstructure examinations showed that the superimposed ultrasonic vibration in micro-tension could lead to the retardation of texture evolution, the decreases in kernel average misorientation (KAM) value, low-angle grain boundary (LAGB) fraction and dislocation density in titanium foils, which somewhat supported our model assumptions in terms of the acoustic energy dependent reduction in dislocation density and the enhanced dislocation ejection causing the improvement of plastic compatibility.

High-added-value biomass-derived composites by chemically coupling post-consumer plastics with agricultural and forestry wastes

Currently, the ever-increasing post-consumer polypropylene (PP) plastics and agricultural and forestry wastes that are relatively difficult to be degraded have led to serious resource waste and environmental pollution. To achieve the rational utilization of resources and meanwhile reduce the potential influences on ecological environment, in this study, high-added-value biomass-derived composites were produced by chemically coupling post-consumer plastics with agricultural and forestry wastes (e.g. pine nutshell and corn straw) in the presence of interfacial compatibilizers. In terms of chemical composition, the as-proposed compatibilizer contains CC bonds and NCO group, which can be effectively enhance the interfacial compatibility and mechanical stability of hydroxyl-rich biomass wastes and plastics. Experimental results conclude that the highest tensile strength of forestry pine nutshell/PP composite is 25.44 MPa and the flexural strength is 47.84 MPa with the assistance of 5.0 wt% compatibilizer. If agricultural corn straw is used as the raw materials, the highest flexural strength of corn straw/PP composite is 42.94 MPa and the tensile strength is 22.60 MPa under the same experimental conditions. Besides the improved mechanical properties, the thermal stability and water retardation capacity of the produced biomass-waste/PP composites is enhanced with the addition of the chemical compatibilizer as confirmed by thermal gravimetric analysis and water absorption measurements. This conversion of the post-consumer plastics and the biomass wastes into the environmentally benign high-added-value composite materials is favorable to promote the recycling economy and achieve the recyclable utilization of these wastes that are harmful to environment.

Compatibility of energetic plasticizers with the triblock copolymer of polypropylene glycol-glycidyl azide polymer-polypropylene glycol (PPG-GAP-PPG)

Abstract Glycidyl azide polymer (GAP) is well known as an energetic prepolymer, but its application as a binder in propellants is limited due to its relatively high glass transition temperature and relatively poor mechanical properties. Copolymerization of GAP with polypropylene glycol (PPG) has been shown to improve GAPs properties because of the good thermal and mechanical properties of PPG. In this research we synthesized triblock copolymer of PPG-GAP-PPG and the compatibilities of this copolymer were investigated with energetic plasticizers (20% w/w) n-butyl nitroxyethylnitramine (BuNENA), trimethylolethane trinitrate (TMETN), and butanetriol trinitrate (BTTN) by solubility parameter, differential scanning calorimetry (DSC), rheological analysis, scanning electron microscopy (SEM) and vacuum stability test (VST). The DSC results showed that BuNENA had better compatibility with the triblock copolymer in comparison to TMETN and BTTN. It reduced the T g of PPG-GAP-PPG from −58 to −63 °C. The rheological analysis was in good agreement with the DSC results obtained for the compatibility of the plasticizers. In the case of the addition of 20% w/w BuNENA, the viscosity of copolymer/plasticizer decreased from 550 to 128 mPa s, indicating appropriate compatibility of plasticizer with the copolymer. SEM images showed a better distribution of BuNENA in the copolymer matrix.

Synthesis and Thermal Decomposition Kinetics of Epoxy Poly Glycidyl Nitrate as an Energetic Binder

An energetic binder epoxy poly glycidyl nitrate (e-PGN) with a molecular weight of about 1244 gr/mol was synthesised via end modified poly glycidyl nitrate (PGN) is presented in the paper. This structure was characterised by the number of epoxy groups, infrared spectroscopy, and nuclear magnetic resonance. The thermal degradation behavior of e-PGN was studied by thermo gravimetric analysis (TG) and differential scanning calorimetry (DSC) under nitrogen atmosphere at different heating rates. The glass transition temperature (Tg) was measured to determine the compatibility of energetic plasticizer with the binder in the mixture of plasticizer/binder and compared with the results of e-PGN, and initial decomposition temperature in e-PGN was studied using the DSC method. The DSC results showed that the glass transition temperature of a mixture of 20 % Bu-NENA/e-PGN mixture (Tg = −56 °C) was lower than e-PGN (Tg = −37.78 °C) that shows the most compatible plasticizer is Bu-NENA. The activation energy of degradation e-PGN and e-PGN-20% Bu-NENA were calculated with DSC by the model-free methods and compared with the results of AKTS software in version 3.51(2013-07-10). The activation energy of exothermic decomposition of the e-PGN and e-PGN-20% Bu-NENA were calculated by the Kissinger, Flynn–Wall–Ozawa, Starink, and AAdvanced kinetics and technology solutions (Friedman) methods. Finally, the half-life prediction of the e-PGN and e-PGN-20% Bu-NENA were investigated.

Identification and analysis of anomalous {[formula omitted]} twins in an extruded Mg-2wt%Y alloy sheet during uniaxial tensile loading

The deformation behaviors of a hot-extruded Mg-2wt%Y alloy sheet with high activity for basal slip was studied under uniaxial tensile loading along the extrusion direction at room temperature. Using electron backscatter diffraction and crystal plasticity finite element method (CPFEM) simulation, this work proposed the direct evidence for the activation and the role of anomalous {101‾2} twinning: (1) In the Mg alloy with high activity for basal slip, anomalous {101‾2} twins were indeed identified during tensile loading rather than unloading. The anomalous twins had the highest or the third highest negative Schmid factors of {101‾2} twinning, while the normal twins had positive Schmid factors. (2) During tensile loading, the anomalous twins were more easily activated than normal twins. As the true strain increased, the amounts of anomalous twins increased faster than the amounts of normal twins. (3) The normal twins induced positive shear strain along the loading direction while the anomalous twins induced negative shear strain along the loading direction. The role of anomalous twinning was accommodating the plastic compatibility and improving the ductility.

Radiolysis as a Powerful Tool for Polymer Waste Recycling

The review is devoted to the use of ionizing radiation for the processing of polymer wastes including the application of radiolytic effects to the sorting of plastics; an increase in the compatibility of plastics with cement, asphalt, and other materials; the destruction of high-molecular-weight wastes; the synthesis of multicomponent polymer composites; the production of monomers for the synthesis of conventional and alternative plastics; the manufacture of antioxidants; the processing of inseparable mixtures of natural and synthetic polymers; etc. The radiation-induced processes of crosslinking, graft polymerization, oxidation, degradation, and high-temperature conversion in the recycling of polymer wastes are considered.

Genesis and mechanism of microstructural scale deformation and cracking in ZnAlMg coatings

In-depth investigation of the microscale deformation behavior of ZnAlMg coatings is essential to reveal the origin and mechanism of cracking in these coatings. In this work anisotropic microstructural damage and cracking of multiphase Zn1.8Al1.8Mg alloy coatings produced by hot-dip galvanization process on a steel substrate have been studied extensively. Nanoindentation coupled with orientation image microscopy (OIM) is utilized to determine the local micro ductility/strength of the existing phases as well as the orientation dependent micromechanical properties of primary zinc grains. Plastic deformation and damage behavior of the coating are evaluated through in-situ tensile/bending tests, micro-digital image correlation and in-situ OIM analyses. Stress distribution fields and nucleation sites of cracks within the coating microstructure are investigated using extended finite element method. Three quantitative plastic deformation-based criteria are revealed to correlate the coating microstructure to micro-mechanical properties to comprehend the cracking phenomenon. In particular, the binary eutectic is identified as the most detrimental constituent for compatible plastic deformation. Local strain hardening exponent and Schmid factor of primary zinc grains are found to play a significant role in clarifying the cracking behavior. The results of this study are considered as an important step towards designing microstructure controlled ZnAlMg coatings with superior formability.

Examining the compatibility of energetic plasticizer DNDA-5 with energetic binders

The requirement of developing energetic binders with suitable energetic plasticizers is to enhance the mechanical properties and to reduce glass transition temperature of propellant and explosive formulations. Compatibility of energetic plasticizer 2,4-dinitro-2,4-diazapentane (DNDA-5) with four different energetic binders viz. poly glycidyl nitrate (PGN), poly(3-nitratomethyl-3-methyloxetane) (PLN), glycidyl azide polymer (GAP) and tetra functional glycidyl azide polymer (t-GAP) was studied by using differential scanning calorimeter (DSC) and density functional theory (DFT) methods. Results obtained for the pure binder was compared with the results obtained for binder/plasticizer blend in the parameters of decomposition temperature and the format of the peak which indicated the compatibility or incompatibility of DNDA-5 with the studied binders. Glass transition temperatures of all these blends were determined by low temperature DSC and showed desirable lowering of glass transition temperature with single peak in the case of PLN. The proposed energetic plasticizer DNDA-5 has displayed its compatibility with three binders PGN, PLN and GAP employing thermal techniques. DNDA-5 has been found as incompatible when it is mixed with t-GAP. The predicted relative trend of interaction energies between plasticizer and binder has provided concurrence to results drawn from thermal studies.

Molecular dynamics simulation study on the mechanism of NPBA enhancing interface strength of NEPE propellant

In this article, Molecular dynamics (MD) simulation were applied to investigate the adsorption behavior and mechanism of neutral polymeric bonding agents (NPBA) in nitrate ester plasticized polyether (NEPE). The simulation results indicate that due to the strong van der Waals (vdW) force interaction, NPBA has the highest binding energy with RDX compared to PEG and nitrate plasticizer. Then, the influences of temperature on the compatibility of nitrate plasticizer and two polymers, NPBA and PEG, were studied. The results show that PEG can dissolve in nitrate plasticizer over a wide range of temperature, while the compatibility of NPBA and nitrate plasticizer decrease with the reducing of temperature. Moreover, the adsorption behavior of the NPBA on RDX surface in nitrate plasticizer was investigated. The results demonstrate that the NPBA chains can penetrate through nitrate plasticizer, adsorb on the RDX surface, and form a compact protection layer, which prevents the bonding interface from nitrate plasticizer damage. Our researches afford a microscopic insight into the mechanism of NPBA, and can be helpful to the NPBA molecular and NEPE formulation design.

A Hierarchical Approach for Solving Simultaneous Lot Sizing and Scheduling Problem with Secondary Resources

This study represents a decomposition heuristic approach for simultaneous lot sizing and scheduling problem for multiple product, multiple parallel machines with secondary resources. The motivation of the study comes from the real-world instance of a plastic injection plant at Vestel Electronics. The plastic injection plant requires plastic injection molds at the planner’s disposal, in order to produce variations of products, by the compatible plastic injection machines. The variations on the molds and the mold changes on the machines bring out sequence dependent major and minor setups. Since each machine requires an operator, we have extended the formulation with workforce and shift planning. Results show that proposed heuristic yields comparable solutions to that of exact model for small and medium size instances; and provides schedules for the large size instances, for which exact model cannot find a feasible solution in the allotted time.

Mechanical properties of poly(lactid acid) plasticized by cardanol derivatives

This work is aimed to study the effect of cardanol derived plasticizers on the tensile modulus of poly(lactic acid), PLA. Neat cardanol, cardanol acetate (CA), and epoxidized cardanol acetate (ECA) were used, at contents ranging between 10% and 30%. For comparison purposes, another green plasticizer, poly(ethylene glycole) (PEG), was used. Tensile tests were carried out to evaluate the influence of the type and the amount of plasticizer on the tensile modulus of injection molded PLA. Within the examined composition limits, PLA plasticized by cardanol derivatives showed lower modulus than PEG plasticized PLA. The tensile modulus of plasticized PLA was correlated to the evolution of glass transition temperature and degree of crystallinity. At low plasticizers content, the modulus of PLA decreased as the glass transition temperature decreased, due to a better miscibility of the plasticizer with PLA. The opposite occurred at high plasticizer content; in this case, the higher modulus found for more compatible plasticizers were attributed to an increased crystallization kinetic. The evolution of elastic modulus as a function of glass transition temperature and degree of crystallinity was analyzed using a single equation capable to fit the data obtained using different plasticizers.