Plastic Compatibility Research Articles

Texture evolution in Mg–Mn and Mg–Mn–Ce alloys and the effect of as-cast grain size

Texture evolution in rolled (400°C) and annealed (450°C) Mg–1% Mn-based alloys containing different levels of Ce was examined. It was found that Ce refines the as-cast and rolled/annealed grain structure. The overall intensity of the basal texture decreases with Ce additions in both the rolled and subsequently annealed condition. A strong relationship was found between maximum intensity (M) of rolling and annealing textures and the as-cast effective grain size, d ′, i.e. M ∝ e0.4 d ′ (R 2 = 0.8), which was attributed to the role of plastic compatibility stresses which lead to grain boundary deformation altering the balance of deformation modes. Contributions from Ce solute effects and lattice parameter changes are also discussed.

A Simple, Semiquantitative Device for Liquid–Liquid Separations

A simple liquid–liquid separation device is prepared using a plastic syringe and compatible plastic stopcock. The design allows students to carry out quantitative extractions using a variety of organic solvents. Extraction yields are found to be equally precise and more accurate compared to glass separatory devices. The plastic separatory device is much more economical than the glass counterpart and is far more resistant to breakage. The design allows for simple adaptation to a variety of different syringes, further lowering material costs in the teaching lab.

Rheometric study of the gelation and fusion processes of poly(vinyl chloride‐co‐vinyl acetate) plastisols with different commercial plasticizers

AbstractEvolution of the complex viscosity of pastes of PVC‐VA (vinyl chloride‐vinyl acetate copolymer) plasticized with different commercial plasticizers has been studied. Knowledge of the rheological behavior of the formulations allows for better understanding of the gelation and fusion processes. Twenty commercial plasticizers of different types and with different functional groups have been studied and are grouped into five families: phthalate esters with linear chains, phthalate esters with branched chains, adipates (normal and polymeric), citrates, and rest of the plasticizers (carboxylates, alkylsulfonates, and pentaerythritol ester derivatives). Interesting relationships among the observed rheologies and the nature and molecular weight of the plasticizer have been observed. The evolution of the complex viscosity with temperature—at the temperatures where the blowing agents normally used in PVC plastisol foaming processes generate the main amount of gas—has been newly discussed with regard to the chemical structure and molecular weight of all of the plasticizers used. It was found that several different dynamic processes must be synchronized in order to understand the relationships among the chemical structure, plasticization, plasticizer compatibility, rheological properties, and foaming process of such materials. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers

Study on edge cracking and texture evolution during 150 °C rolling of magnesium alloys: The effects of axial ratio and grain size

Pure Mg, AZ31 (Mg–3 wt%Al–1 wt%Zn) and experimental alloys, Mg–1 wt%Zn–1 wt%In, Mg–2 wt%Li–1 wt%Zn, Mg–2 wt%Li–1 wt%Zn–1 wt%In were rolled at 150 °C to 0.3 and 0.55 strain. The samples rolled to 0.3 strain were subsequently annealed for 10 min at 400 °C. The texture was evaluated in rolled and in rolled/annealed conditions. The axial ratio ( c/ a) of the alloys strongly influenced edge cracking during rolling (expressed as cracking index, I C), which was explained via the influence of c/ a on the twinning mode. The as-cast grain size did not correlate to I C (edge cracking). Texture intensity was strongly influenced by the as-cast grain size (which was attributed to plastic compatibility at grain boundaries), showed weak correlation to the lattice parameter a, but did not depend on c/ a. The Mg–2 wt%Li–1 wt%Zn alloy, with fine grain size and small c/ a and a, exhibited the optimum combination of weak texture and crack-free rolling at 150 °C.

Preliminary Results of Magnetic Resonance Imaging-aided High-dose-rate Interstitial Brachytherapy for Recurrent Uterine Carcinoma after Curative Surgery

This report presents initial experience with imaging-aided high-dose-rate interstitial brachytherapy (HDR-ISBT) for post-operative recurrence of uterine carcinoma. Fourteen patients presenting with post-operative recurrence of uterine carcinoma (nine cervix and five corpus) between July 2005 and October 2008 were enrolled in this study (median follow-up: 37 months, range: 6-59 months). We implanted magnetic resonance imaging (MRI)-compatible plastic applicators using our own ambulatory technique. HDR-ISBT treatment consisted of twice-a-day irradiation of 6 Gy each with at least a six-hour interval to provide the total prescribed dose. Treatment was based on treatment planning-computed tomography with MRI as a reference. Seven patients were treated with a combination of ISBT (median 30 Gy/5 fractions; range: 27-33 Gy) and external beam radiation therapy (EBRT), and the other seven with brachytherapy only (median 54 Gy/9 fractions; range: 48-54 Gy), one of whom had previously received pelvic EBRT. The three-year estimates of local control and overall survival rates were 77.9% (95% confidence interval (CI): 55.8-100%) and 77.1% (95% CI: 54.2-100%), respectively. Two patients, who had received combined treatment with EBRT showed untoward reactions, including a grade 3 subileus and grade 2 constipation. Another patient, who had been treated with ISBT alone, developed grade 2 urinary constriction. Our imaging-aided HDR-ISBT for post-operative recurrence of uterine carcinoma was found to be practical with promising preliminary results.

ИССЛЕДОВАНИЕ ТЕРМОДИНАМИЧЕСКОЙ СОВМЕСТИМОСТИ ДИБУТИЛФТАЛАТА С КАУЧУКАМИ - КОМПОНЕНТАМИ ТВЕРДОТОПЛИВНЫХ СИСТЕМ

ИССЛЕДОВАНИЕ ТЕРМОДИНАМИЧЕСКОЙ СОВМЕСТИМОСТИ ДИБУТИЛФТАЛАТА С КАУЧУКАМИ - КОМПОНЕНТАМИ ТВЕРДОТОПЛИВНЫХ СИСТЕМ

Molecular Dynamics Simulation on Compatibility of Hydroxyl-Terminated Polybutadiene/Plasticizer Blends

It has been found that the mechanical properties of solid propellants and plastic bonded explosives (PBX) depend heavily on the compatibility of the polymer binder and plasticizer used in their formulation. Two systems, one miscible and the other immiscible, were simulated by molecular dynamics (MD) simulations to test the usefulness of this molecular simulation technique. Density, cohesive energy density, and solubility parameters of hydroxyl-terminated polybutadiene (HTPB), dioctyl sebacate(DOS), nitroglycerine (NG), HTPB/DOS blend and HTPB/NG blend were calculated by MD simulations with the COMPASS force field for the prediction of polymer binder and plasticizer compatibility. Results show that HTPB/DOS is a miscible system but HTPB/NG is not miscible by comparing the difference in the solubility parameter value (△δ), pair correlation function and the change of density. The predictions agreed well with experimental observations. By calculating the pair correlation function the HTPB/plasticizer interaction was clarified. Therefore, the method used in this work is a useful tool to provide information on miscibility and other properties of a given polymer/plasticizer blend. In addition, it is a promising technique to help to design formulations for screening solid propellants and PBX before experimental tests.

A comparative study of plasma-enhanced chemical vapor gate dielectrics for solution-processed polymer thin-film transistor circuit integration

This paper considers plasma-enhanced chemical vapor deposited (PECVD) silicon nitride (SiNx) and silicon oxide (SiOx) as gate dielectrics for organic thin-film transistors (OTFTs), with solution-processed poly[5,5′-bis(3-dodecyl-2-thienyl)-2,2′-bithiophene] (PQT-12) as the active semiconductor layer. We examine transistors with SiNx films of varying composition deposited at 300 °C as well as 150 °C for plastic compatibility. The transistors show over 100% (two times) improvement in field-effect mobility as the silicon content in SiNx increases, with mobility (μFE) up to 0.14 cm2/V s and on/off current ratio (ION/IOFF) of 108. With PECVD SiOx gate dielectric, preliminary devices exhibit a μFE of 0.4 cm2/V s and ION/IOFF of 108. PQT-12 OTFTs with PECVD SiNx and SiOx gate dielectrics on flexible plastic substrates are also presented. These results demonstrate the viability of using PECVD SiNx and SiOx as gate dielectrics for OTFT circuit integration, where the low temperature and large area deposition capabilities of PECVD films are highly amenable to integration of OTFT circuits targeted for flexible and lightweight applications.

Doppler Ultrasound Compatible Plastic Material for Use in Rigid Flow Models

A technique for the rapid but accurate fabrication of multiple flow phantoms with variations in vascular geometry would be desirable in the investigation of carotid atherosclerosis. This study demonstrates the feasibility and efficacy of implementing numerically controlled direct-machining of vascular geometries into Doppler ultrasound (DUS)–compatible plastic for the easy fabrication of DUS flow phantoms. Candidate plastics were tested for longitudinal speed of sound (SoS) and acoustic attenuation at the diagnostic frequency of 5 MHz. Teflon ® was found to have the most appropriate SoS (1376 ± 40 m s –1 compared with 1540 m s –1 in soft tissue) and thus was selected to construct a carotid bifurcation flow model with moderate eccentric stenosis. The vessel geometry was machined directly into Teflon ® using a numerically controlled milling technique. Geometric accuracy of the phantom lumen was verified using nondestructive micro-computed tomography. Although Teflon ® displayed a higher attenuation coefficient than other tested materials, Doppler data acquired in the Teflon ® flow model indicated that sufficient signal power was delivered throughout the depth of the vessel and provided comparable velocity profiles to that obtained in the tissue-mimicking phantom. Our results indicate that Teflon ® provides the best combination of machinability and DUS compatibility, making it an appropriate choice for the fabrication of rigid DUS flow models using a direct-machining method. (E-mail: david.holdsworth@imaging.robarts.ca)

Application of Fourier transform infrared spectroscopy in the study of interactions between PVC and plasticizers: PVC/plasticizer compatibility versus chemical structure of plasticizer

AbstractFourier transform infrared spectroscopy is applied in the study of interactions between PVC resin and plasticizers in flexible PVC systems. The comparison of the theoretical infrared spectra coming from the addition of the respective component infrared spectra with those of PVC/plasticizer experimental systems gives information about polymer/plasticizer interaction degree. In addition, solvation capacity of the plasticizer varies as a function of its chemical structure, giving rise to compatibility differences between the system components. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1731–1737, 2006

Deformation behavior of Mg–Zn–Gd-based alloys reinforced with quasicrystal and Laves phases at elevated temperatures

Mg–Zn–Gd and Mg–Zn–Gd–Cu alloys, reinforced with quasicrystal (I-phase) and Laves phases, have been produced by extrusion process. The deformation behavior of these two alloys at room temperature and at elevated temperatures was investigated, respectively. The Mg–Zn–Gd alloy has high UTS of 305 MPa and elongation of 14.6% due to the strengthening effect of I-phase, while Mg–Zn–Gd–Cu alloy with Laves phases has higher yield stress of 217 MPa due to more strengthening particles and lower elongation of 11.9% resulting from the low content of I-phase and low symmetry of Laves phase due to which it cleaves easily (while the I-phase has a very high symmetry and therefore isotropic in nature). At high temperatures, Mg–Zn–Gd alloy shows large strain due to the excellent plastic compatibility coming from low interfacial energy of I-phase/matrix; Mg–Zn–Gd–Cu alloy has higher level of flow stress, strain exponent and more stable microstructure than Mg–Zn–Gd alloy due to better heat-resistance supplied by collaboration of Laves phases and quasicrystal phase, which can provide more effective pinning effect and suppress grain growth during deformation.

Application of complex esters in poly(vinyl chloride) plastisols and plasticats

PurposeTo evaluate the efficiency of complex esters as plasticizers in polyvinyl chloride plastisols and plasticates.Design/methodology/approachSeveral poly(vinyl chloride) plastisols and plasticates were prepared with standard phthalate plasticizers and complex esters and were characterised using standard and laboratory methods.FindingsThe use of mixtures of three new CE with standard phthalate plasticizers increased the physical, mechanical and electric characteristics of the resulting PVCPs and PVCPl.Research limitations/implicationsThe use of three new CE, obtained by esterification of dicarboxylic acids (adipic, sebacic, pelargonic), poly(ethylene glycol) and i‐octanole, as plasticizers of poly(vinyl chloride) plastisols and plasticates was investigated. The use of CE based on other organic acids could be explored.Practical implicationsThe results confirmed the efficiency of plasticization of PVC by CE. Such a finding has significant industrial implication.Originality/valueSeveral findings are original and are of importance to relevant industry. The new CE with high molecular weights were effective plasticizers of PVC. The efficiency of the plasticizers depended on their chemical structure. The molecular weight of the CE had no influence on the compatibility of plasticizers and other components of the PVC plastisols and plasticates.

Effect of biodegradable plasticizers on thermal and mechanical properties of poly(3-hydroxybutyrate)

The effects of biodegradable plasticizers on the thermal and mechanical properties of poly (3-hydroxybutyrate- co-3-hydroxyvalerate) (PHBV) were studied using thermal and mechanical analyses. Soybean oil (SO), epoxidized soybean oil (ESO), dibutyl phthalate (DBP) and triethyl citrate (TEC) were used as plasticizing additives. PHBV/plasticizer blends were prepared by evaporating solvent from blend solutions. The content of plasticizer in the blends was kept at 20wt%. Compatibility of plasticizer with PHBV was examined with differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). DPB and TEC were more effective than soybean oils (SO and ESO) in depression of the glass transition temperatures as well as in increasing the elongation at break and the impact strength of the films. From the thermal and mechanical properties of the plasticized PHBV, it could be concluded that TEC or DBP are better plasticizers than SO and ESO for PHBV.

The activity of non-basal slip systems and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys

Fine-grained alloys of Mg-3Al-1Zn-0.2Mn in wt.% (AZ31B) were obtained by an equal-channel angular extrusion technique and subsequent annealing at elevated temperatures. Tensile tests were performed at room temperature at a strain rate of 1x10 -3 s -1. The alloys exhibited an apparent steady-state deformation region and a large tensile elongation of 47%. The deformed microstructure at an elongation of 2% indicated substantial cross-slip to non-basal planes induced by plastic compatibility stress associated with grain boundaries. The non-basal segment of dislocations was found to consist of 40% of the total dislocation density at a yield anisotropy factor of only 1.1 instead of an expected value of 100 obtained from single-crystal experiments. The deformed microstructure at an elongation of 16% indicated recovered regions within twins as well as untwinned matrices. These results indicate that dynamic recovery can occur in Mg alloys at room temperature.

Grain-Boundary Sliding in AZ31 Magnesium Alloys at Room Temperature to 523 K

Rolled sheets of AZ31 Mg alloys were subjected to tensile testing at temperatures ranging from room temperature to 523K. The occurrence of grain-boundary sliding (GBS) at room temperature was demonstrated by the displacement of scribed lines across grain boundaries of deformed samples. Surface relief of deformed samples was measured by use of a scanning laser microscope. GBS strain was calculated from the measured surface step height, and its temperature dependence was analyzed by a Dorn-type constitutive equation. GBS above 423K was found to be pure GBS that was activated by resolved applied shear stress acting on grain boundaries. The activation energy for GBS was found to be 80 kJ/mol, which is in agreement with the activation energy for grain boundary diffusion. Meanwhile, GBS below 373K was found to be slipinduced GBS, and its extent was found to be significantly greater than that expected from extrapolation of high-temperature values. The slipinduced GBS is considered to occur by plastic compatibility conditions in the presence of plastic strain anisotropy and by absorption and dissociation of lattice dislocations at grain boundaries.

Compatibility of plastics with cytotoxic drug solutions—comparison of polyethylene with other container materials

In this study low density polyethylene (LDPE)-containers were compared to glass bottles and polyvinyl chloride (PVC) bags in view of adsorption effects with antineoplastic drugs. The infusion containers were supplemented with therapeutic doses of the nine common cytotoxic drugs carboplatin, carmustine, cytarabine, dacarbazine, fluorouracil, gemcitabine, melphalan, methotrexate and vinorelbine. 0.9% isotonic sodium chloride solution and 5% dextrose served as infusion solutions. The containers were stored at room temperature or at 4°C, protected from light, for periods of up to 168 h. Turbidity, change of colour and visible crystallization were not observed. Samples were collected at different time intervals and drug contents were determined with high-performance liquid chromatography (HPLC). Preparations of carmustine showed no adsorption phenomena when stored in LDPE or in glass at 4°C. At room temperature in LDPE, a slight decrease in concentration due to adsorption was monitored. However the drug loss in PVC bags was greater. Dacarbazine and melphalan showed decreases in concentration, which were independent on the type of container material. The remaining analyzed agents showed no drug loss at all. In conclusion, investigated drugs were stable in all three container types, with the best stability in glass bottles, followed by LDPE and PVC.

Mechanical properties of materials and the object of description in gauge theories

In the continuum theory of defects the total strain of an inelastic material can be represented by the sum of the reversible elastic strain associated with external loads, the compatible elastoplastic strain due to defects of the material, and the compatible plastic strain responsible for irreversible deformation of the material. The proposed scheme of separation of the strain into distinct components can be used to determine the physical significance of the inelastic properties of materials and the object of description of a gauge model representing a dynamical generalization of the continuum theory of defects.

The influence of the compatibility of plasticizers with polymer ionic conductors on ionic conduction

The influence of the compatibility of plasticizers on the aggregated structure and the ion-conductive behavior of poly(ethylene oxide)/lithium methoxy di (ethyleneoxy) phenylsulfonate (EO2PSLi) complex were studied using two plasticizers with different polarity, γ-butyrolactone (BL) and 2,5-di(methyl diglycol)-1,4;3,6-dianhydrous sorbitol ether (DGS), a novel pincer-like plasticizer synthesized in this paper. The DGS can effectively destroy the PEO crystalline phase in PEO/EO2PSLi complex and increase the amorphous area in which Li+ cations transport, depending on polymeric segmental movement. However, in BL-plasticized PEO/EO2PSLi complex, the highly polar BL hardly disrupts PEO crystals and only forms a BL-rich phase, a kind of liquid electrolyte tunnel in which Li+ mainly transfers.

Effect of plasticizer-polymer compatibility on the response characteristics of optical thin CO 2 and O 2 sensing films

A homologous family of dialkyl phthalates has been used to investigate the effect of plasticizer/polymer compatibility on the response characteristics of transparent, plastic, thin optical gas sensing films for CO 2 and oxygen. Plasticizer/polymer compatibilities were determined through the value of the difference in solubility parameter, i.e. Δ δ, for the plasticizer and polymer with a Δ δ value of zero indicating high compatibility. A strong correlation was found between plasticizer/polymer compatibility and sensitivity in phenol red/ethyl cellulose CO 2-sensitive films and this relationship extended to CO 2-sensitive films based on other polymers such as polystyrene and poly(methyl methacrylate). It extended also to optical O 2-sensitive films implying that the relationship is general for thin-film optical sensors. Other results from the CO 2-sensitive films in different polymers indicated that the film sensitivity is largely independent of the polymer matrix regardless of its inherent gas permeability, when a sufficient quantity of compatible plasticizer is present.

Infrared spectral changes in PVC and plasticized PVC during gelation and fusion

The behaviour of PVC and PVC plastisols has been studied during their thermal treatment using an in situ FTIR technique. The plasticizer introduces certain modifications in the spectrum of the resin which are more marked in the case of the more compatible plasticizers. The A 1427 A 1435 and A 637 A 616 ratios of the intensities of the crystalline and amorphous bands of the resins, decrease in the plastisols when increasing the compatibility of the plasticizer. On the other hand, when the plastisol undergoes the gelation process, a great decrease of these ratios is observed, showing that the increase in temperature produces a decrease in the amount of the crystalline phase in the resin with respect to the amorphous phase. This behaviour has also been observed when the resin is heated without plasticizer, and is a reversible process. The CO band corresponding to the plasticizer shows a different behaviour to the resin bands. When the temperature increases, a shift to lower wavenumbers is observed. This displacement is irreversible (the band does not recover its original location after cooling) and the process occurs in a relative narrow temperature interval. This temperature range, where the carbonyl band suffers these changes, is in good agreement with the gelation temperature as measured by other techniques.