Manufacture Of Poly Research Articles

Material Extrusion-Based Additive Manufacturing of Poly(Lactic Acid) Antibacterial Filaments-A Case Study of Antimicrobial Properties.

In the era of the coronavirus pandemic, one of the most demanding areas was the supply of healthcare systems in essential Personal Protection Equipment (PPE), including face-shields and hands-free door openers. This need, impossible to fill by traditional manufacturing methods, was met by implementing of such emerging technologies as additive manufacturing (AM/3D printing). In this article, Poly(lactic acid) (PLA) filaments for Fused filament fabrication (FFF) technology in the context of the antibacterial properties of finished products were analyzed. The methodology included 2D radiography and scanning electron microscopy (SEM) analysis to determine the presence of antimicrobial additives in the material and their impact on such hospital pathogens as Staphylococcus aureus, Pseudomonas aeruginosa, and Clostridium difficile. The results show that not all tested materials displayed the expected antimicrobial properties after processing in FFF technology. The results showed that in the case of specific species of bacteria, the FFF samples, produced using the declared antibacterial materials, may even stimulate the microbial growth. The novelty of the results relies on methodological approach exceeding scope of ISO 22196 standard and is based on tests with three different species of bacteria in two types of media simulating common body fluids that can be found on frequently touched, nosocomial surfaces. The data presented in this article is of pivotal meaning taking under consideration the increasing interest in application of such products in the clinical setting.

Manufacturing of poly(ethylene glycol diacrylate)-based hollow microvessels using microfluidics.

The microvasculature is a vital organ that distributes nutrients within tissues, and collects waste products from them, and which defines the environmental conditions in both normal and disease situations. Here, a microfluidic chip was developed for the fabrication of poly(ethylene glycol diacrylate) (PEGDA)-based hollow self-standing microvessels having inner dimensions ranging from 15 μm to 73 μm and displaying biocompatibility/cytocompatibility. Macromer solutions were hydrodynamically focused into a single microchannel to form a concentric flow regime, and were subsequently solidified through photopolymerization. This approach uniquely allowed the fabrication of hollow microvessels having a defined structure and integrity suitable for cell culturing.

Layer-by-Layer Assembled Nanoparticles for siRNA Delivery.

Nanoparticles synthesized via layer-by-layer processes are promising candidates for successful drug and gene delivery. Widespread use of the layer-by-layer technique has resulted from its accessibility to every lab; to generate nanoscale structures, layer-by-layer processes require common lab equipment of only modest quality and do not involve the use of organic solvents. In addition, a wide range of different starting materials can be flexibly combined, enabling the production of a nearly unlimited number of different nanoparticles (NP) with various physicochemical properties. Here we describe the manufacturing of poly(lactic-co-glycolic acid) NPs coated with siRNA for gene silencing. Positively charged polyethyleneimine and negatively charged nucleic acids form the polyelectrolyte shell. Finally, the NPs are functionalized with hyaluronic acid, a polysaccharide which targets the CD44 receptor.

Poly(aniline-co-o-anisidine)/graphene oxide Au nanocomposites for dopamine electrochemical sensing application

We describe here the manufacture of poly(aniline-co-o-anisidine)/graphene oxide nanocomposites, with the common abbreviation [PANI-co-PoAN/GO1−5], by the well-known in situ oxidative polymerization method with ultrasonic assistance. FE-SEM and TEM micrographs were utilized to examine the morphological characteristics of the composite materials. Moreover, FT-IR, XRD, TGA, and electrical conductivity measurements were used to investigate their complete performance. All the composites had almost equal final copolymer decomposition temperatures, which were in the range of 609.3–663.8 °C. Our essential objective is to study the electro selective application using gold nanoparticles (AuNPs) as a coating. Dopamine (DA) electrochemical sensor based on [AuNPs/PANI-co-PoAN/GO] nanocomposite covalently modified gold electrode was modified by an electroabsorption technique. The electrochemical behavior of the modified electrode towards the oxidation of DA was studied by square wave voltammetry (SWV) and cyclic voltammetry (CV) in pH 5.0 phosphate buffer solution. The sensor developed a current response to the oxidation of DA. Using SWV, the electrochemical sensor gave a linear relationship to DA in the concentration range of 5–100 µM with a limit of detection of 0.0334 µM. The modified electrode was highly stable, sensitive, and selective.

Compounding Oil Palm Empty Fruit Bunch/Cotton Fiber Hybrid Reinforced Poly(lactic acid) Biocomposites Aiming For High-temperature Packaging Applications

The manufacture of poly(lactic acid) (PLA) composites reinforced with both oil palm empty fruit bunch (EFB) and cotton fiber was investigated. The positive and significant effect of EFB on the heat distortion temperature (HDT) and flexural properties was determined by a 2k design of experiment study. Adding solid epoxy into the PLA matrix manifested inferior mechanical properties with no improvement to the HDT. The HDT and mechanical properties of the biocomposites were further improved by using an EFB/cotton hybridized system. The PLA/hybridized EFB/cotton biocomposites showed biodegradability and an HDT higher than 100 °C. However, the flowability of the material was retarded at high cotton fractions. Finally, adding talc filler into the biocomposites improved the flowability of the hybridized biocomposite systems, especially at low fiber and high talc contents. Nevertheless, inferior mechanical properties of the biocomposites were found for high talc and low fibers’ contents.

Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification.

Accurate control of particle size at relatively narrow polydispersity remains a key challenge in the production of synthetic polymer particles at scale. A cross-flow membrane emulsification (XME) technique was used here in the preparation of poly(methyl methacrylate) microspheres at a 1-10 l h(-1) scale, to demonstrate its application for such a manufacturing challenge. XME technology has previously been shown to provide good control over emulsion droplet sizes with careful choice of the operating conditions. We demonstrate here that, for an appropriate formulation, equivalent control can be gained for a precursor emulsion in a batch suspension polymerization process. We report here the influence of key parameters on the emulsification process; we also demonstrate the close correlation in size between the precursor emulsion and the final polymer particles. Two types of polymer particle were produced in this work: a solid microsphere and an oil-filled matrix microcapsule.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

Fluid phase behavior of ethylene glycol + water mixtures (at operating conditions of the first-stage esterification reactors for PET synthesis) by molecular simulations and activity coefficient (γ–φ) method

Phase-equilibria of binary mixtures for ethylene glycol (EG)+water mixtures are predicted by employing molecular simulations and the activity coefficient (γ–φ) method. The temperature–composition (T–x–y) diagram at 99.6kPa and the pressure–composition (P–x–y) diagram of EG+water mixtures at 395.15K have been generated using the Gibbs ensemble Monte Carlo simulations and the activity coefficient (γ–φ) method for comparison with that reported in literature. The phase diagram of this system at the operating conditions (405.3kPa) in the first-stage esterification reactor used in the manufacture of poly(ethylene terephthalate), PET, (from terephthalic acid and EG) has been predicted using both the approaches. These results can be used to improve the design of separators and reactors used in PET synthesis.

Synthesis of Biobased Terephthalic Acid from Cycloaddition of Isoprene with Acrylic Acid

A reaction sequence has been elaborated that could enable the 36 × 109 kg/y of terephthalic acid currently synthesized from p-xylene and used in the manufacture of poly(ethylene terephthalate) (PET) to instead be synthesized via cycloaddition of biobased acrylic acid and biobased isoprene. A central challenge in this cycloaddition is isoprene polymerization catalyzed by acrylic acid that is accelerated by the same Lewis acid catalysts needed to improve para selectivity in the cycloaddition. Esterifying acrylic acid to avoid diene polymerization while enabling Lewis acid catalyzed cycloaddition is not atom economical. A solution has been found with TiCl4 (2 mol %) catalyzed cycloaddition of acrylic acid and isoprene. At room temperature and in the absence of solvent, cycloaddition (94% yield) gives a 23:1, para:meta selectivity. Pd(0)-catalyzed aromatization (77% yield) of the para cycloaddition product affords p-toluic acid that is converted (94% yield) into terephthalic acid with a Co2+/Mn2+-catalyzed O2 oxidation.

Automated control of the preform reheating process in the manufacturing of poly(ethylene terephthalate) containers. Part II. Identification of the dynamical properties of controlled object

Automated control of the preform reheating process in the manufacturing of poly(ethylene terephthalate) containers. Part II. Identification of the dynamical properties of controlled object

Poly (vinylidene fluoride) Thin Film Prepared by Roll Hot Press

Various methods have been developed in the manufacture of Poly (vinylidene fluoride) (PVDF) thin films such as coating, spreading, evaporation and calendaring. The method of making this film certainly has many advantages and disadvantages as in the case of operational processes and also the cost of the required treatment. In this paper, an alternative method to preparation of PVDF thin films has been done through the development calendaring method by using roll hot press. The advantages of roll hot press are simple in terms of operation and relative low cost. PVDF thin film has been produced for several temperatures of roll hot press with several different thicknesses. The PVDF thin films are characterized using X-Ray Diffraction and IR spectra. In addition to determine the surface resistivity are caried out using I-V meter. We found that an increase in β fraction of PVDF thin films with increasing temperature at fixed film thickness, while the surface resistivity of PVDF film are decreased. This shown that the piezoelectric property of PVDF films has been

Fluorescent-tagged maleic anhydride-allylpolyethoxy carboxylate copolymer as an environmentally benign inhibitor for calcium phosphate in industrial cooling systems

Allyloxy polyethoxy ether (APEG) and succinic anhydride were used to prepare allyloxy polyethoxy carboxylate (APEL). 8-hydroxy-1,3,6-pyrene trisulfonic acid trisodium salt (PY) was reacted with allyl chloride to produce fluorescent monomer 8-allyloxy-1,3,6-pyrene trisulfonic acid trisodium salt (PA). APEL and PA were copolymerized with maleic anhydride (MA) to synthesize PA tagged no phosphate and nitrogen-free calcium phosphate inhibitor POLY(MA–APEL–PA). Structures of PA, APEG, APEL, and POLY(MA–APEL–PA) were carried out by FTIR and 1H-NMR. Different MA : APEL mole ratios were employed for the manufacture of POLY(MA–APEL–PA) to study the effect of mole ratio on performance of POLY(MA–APEL–PA). Relationship between POLY(MA–APEL–PA)'s fluorescent intensity and its dosage was studied. The results indicate that capability of POLY(MA–APEL–PA) is heavily depended on the mole ratio of MA : APEL. Correlation coefficient r of POLY(MA–APEL–PA)'s fluorescent intensity and its dosage is 0.9999, and detection limit of POLY(MA–APEL–PA) is 0.86 mg/L. POLY(MA–APEL–PA) can be used to accurately measure polymer consumption on line besides providing excellent calcium phosphate inhibition. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Process Capability Analysis in the Manufacturing of Pet Bottles

Modern process control is based on the use of statistical methods to improve and ensure quality, and thus reduce the process cost due to waste and rejects. The paper deals with the process capability analysis in the manufacturing of poly(ethylene-terephthalate) bottles for packaging of table oil. PET bottles are manufactured by the procedure of injection stretch blow moulding. The preforms made by injection moulding are biaxially extruded in the blow mould, with blow parameters affecting the mechanical properties, the barrier properties and the transparency of the manufactured bottle. The performance of blow moulding machine was monitored by measuring the volumes of blown bottles. Based on the collected data, the capability analysis of the blow moulding process was conducted.

Manufacture of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogel tubes for use as nerve guidance channels

Hydrogel tubes of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (p(HEMA-co-MMA)) made by liquid–liquid centrifugal casting are being investigated as potential nerve guidance channels in the central nervous system. An important criterion for the nerve guidance channel is that its mechanical properties are similar to those of the spinal cord, where it will be implanted. The formulated p(HEMA-co-MMA) tubes are soft and flexible, consisting of a gel-like outer layer, and an interconnected macroporous, inner layer. The relative thickness of the gel phase to macroporous phase is controlled by the formulation chemistry, and specifically by the ratio of co-monomers, HEMA and MMA. By varying the surface chemistry of the mold within which the tubes are synthesized, tubes were prepared with either a “cracked” or a smooth outer morphology. Tubes with the cracked outer morphology had periodic channels that traversed the wall of the tube, which resulted in a lower modulus than smooth outer morphology tubes, yet likely greater diffusive permeability. For tubes (and not rods) to be formed, phase separation must precede gelation as is detailed in a formulation phase diagram for HEMA, MMA and water. The tensile elastic modulus of p(HEMA-co-MMA) tubes reflected the formulation chemistry, with greater moduli (up to 400 kPa) recorded for tubes having 10 wt% MMA. The p(HEMA-co-MMA) tubes therefore had similar mechanical properties to those of the spinal cord, which has a reported elastic modulus range between 200 and 600 kPa.

Determination of polyvinyl alcohol in a poly(DL-lactide-co-glycolide) matrix by size exclusion chromatography using evaporative light scattering detection.

Polyvinyl alcohol (PVA) is used in the manufacture of poly(DL-lactide-co-glycolide) (PLGA) microparticles for the delivery of drugs in an injectable implant form. The levels of residual PVA may affect the release or injectability of the microparticles, and thus must be controlled. Previous work had shown the use of visible detection of iodine-borate complexes of PVA, but this was found to be insensitive and prone to interferences from other formulation components and the sample solvents required. Refractive index detection did not appear to be sensitive enough to detect low levels of PVA. Evaporative light scattering detection was found to be more sensitive and less prone to interferences from the sample matrix than refractive index, and gave reproducible results with acceptable recoveries.

Modelling of poly(ethylene terephthalate) in injection stretch–blow moulding

Simulations of the injection stretch–blow moulding process have been developed for the manufacture of poly(ethylene terephthalate) bottles using the commercial finite element package ABAQUS/standard. Initially a simulation of the manufacture of a 330 mL bottle was developed with three different material models (hyperelastic, creep, and a non-linear viscoelastic model (Buckley model)) to ascertain their suitability for modelling poly(ethylene terephthalate). The Buckley model was found to give results for the sidewall thickness that matched best with those measured from bottles off the production line. Following the investigation of the material models, the Buckley model was chosen to conduct a three-dimensional simulation of the manufacture of a 2 L bottle. It was found that the model was also capable of predicting the wall thickness distribution accurately for this bottle. In the development of the three-dimensional simulation a novel approach, which uses an axisymmetric model until the material reaches the petaloid base, was developed. This resulted in substantial savings in computing time.

Liquid—liquid extraction and reversed phase chromatographic behaviour of some 3d metal ions using bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301)

Studies have been carried out on the extraction behavior of some metal ions of the first transition series using bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301) from mineral acid media. The effect of various parameters influencing the extraction such as the nature of the diluent, concentration of the acid and the extractant on the distribution has been investigated. Based on the distribution data some binary separations have been proposed. A flow sheet of a scheme is given for the recovery of manganese free cobalt from a spent catalyst used in the manufacture of poly(ethyleneterepthalate).

Measurement of the melting points of oligomers obtained in the manufacture of poly(ethylene terephthalate)

AbstractThe melting points (Tm) were measured for oligomers obtained by a direct continuous esterification process between terephthalic acid and ethylene glycol. Multiple regression analyses of data were carried out, and an equation was obtained for predicting melting points with correlation coefficient of ∼0.99.