Search results for "Plastics"

Effect of pressure on the PVT behaviour of iPP as revealed by dilatometric measurements

2002

Isotactic Poly-propylene samples, previously prepared under known conditions of pressure and cooling rate by means of a special apparatus designed and set-up by the authors, were subjected to several isobaric runs at low cooling and heating rate in a confining fluid dilatometer (by GNOMIX). The effect of the previous thermo-mechanical histories and the effect of pressure in the dilatometry on specific volume of the samples was studied. Results show that the initial specific volume depends upon the previous thermo-mechanical histories, which however cancels out after the first heating run. Moreover the reported dilatometric experimental data support the evidence that an increase of pressure …

Poly-left-lactic acid tubular scaffolds via diffusion induced phase separation: Control of morphology

2013

n this work, tubular poly-left-lactic acid scaffolds for vascular tissue engineering applications were produced by an innovative two-step method. The scaffolds were obtained by performing a dip-coating around a nylon fiber, followed by a diffusion induced phase separation process. Morphological analysis revealed that the internal lumen of the as-obtained scaffold is equal to the diameter of the fiber utilized; the internal surface is homogeneous with micropores 1–2 μm large. Moreover, a porous open structure was detected across the thickness of the walls of the scaffold. An accurate analysis of the preparation process revealed that it is possible to tune up the morphology of the scaffold (w…

Composite Coatings of Chitosan and Silver Nanoparticles Obtained by Galvanic Deposition for Orthopedic Implants

2022

In this work, composite coatings of chitosan and silver nanoparticles were presented as an antibacterial coating for orthopedic implants. Coatings were deposited on AISI 304L using the galvanic deposition method. In galvanic deposition, the difference of the electrochemical redox potential between two metals (the substrate and a sacrificial anode) has the pivotal role in the process. In the coupling of these two metals a spontaneous redox reaction occurs and thus no external power supply is necessary. Using this process, a uniform deposition on the exposed area and a good adherence of the composite coating on the metallic substrate were achieved. Physical-chemical characterizations were car…

Effect of Microplastics in Hydrothermal Liquefaction (HTL) of Real Municipal Sludge (RMS)

2022

The work herein was focused to study the effect of the microplastics on the yield and quality of biocrude (BC) produced by hydrothermal liquefaction (HTL) of real municipal sludge (RMS). HTL experiments with RMS containing 3 % w/w microplastics were conducted at 325 °C and 30 min both in the absence and in the presence of CoMo/Al2O3, NiMo/Al2O3 and activated carbon felt (ACF) as heterogeneous catalysts. A white wax was isolated from BC with a yield of 5, 8 and 6 % w/w daf when CoMo/Al2O3, NiMo/Al2O3 and ACF were used respectively. GC-MS analyses demonstrated that oleamide was present in the wax while FT-IR analyses showed the presence of chlorinated organic compounds, affecting negatively t…

The synthesis and condensation of oligo(phenylenevinylene)s with alkoxysilyl end groups

2002

Monodisperse alkoxylated oligo(phenylenevinylene)s with 3, 4, or 5 benzene rings were connected to reactive di- and triethoxysilanes, either directly or via flexible spacers. Aminopropylsilanes were condensed with stilbenoid aldehydes and subsequently reduced to amines, for the direct, rigid connection, the Heck reaction and also cross-metathesis with vinyl silanes proved to be successful routes. Hydrolysis of the ethoxysilanes leads to polymerisable cyclosiloxanes or curable three-dimensional networks with pendent chromophores.

Corrigendum to “The effect of silica nanoparticles on the morphology, mechanical properties and thermal degradation kinetics of PMMA” [Polym Degrad S…

2012

Novel silicon microparticles to improve sunlight stability of raw polypropylene

2015

Oxidation of polyolefins by ultraviolet/visible irradiation is a significant limitation for their use in several technological applications. The use of high-tech additives such as silicon microparticles becomes a compositing strategy that can improve the performance of these materials at long-term service conditions. Silicon particles were added to non-additivated raw polypropylene (PP) prepared by hot melt extrusion and subjected to accelerated sunlight irradiation tests. The stability of thermal properties, mechanical performance and thermal decomposition behaviour of composites was evaluated by differential scanning calorimetry, dynamic mechanical thermal analysis and thermogravimetry. T…

Cooperative Catechol-Functionalized Polypept(o)ide Brushes and Ag Nanoparticles for Combination of Protein Resistance and Antimicrobial Activity on M…

2018

Prevention of biofouling and microbial contamination of implanted biomedical devices is essential to maintain their functionality and biocompatibility. For this purpose, polypept(o)ide block copolymers have been developed, in which a protein-resistant polysarcosine (pSar) block is combined with a dopamine-modified poly(glutamic acid) block for surface coating and silver nanoparticles (Ag NPs) formation. In the development of a novel, versatile, and biocompatible antibacterial surface coating, block lengths pSar were varied to derive structure-property relationships. Notably, the catechol moiety performs two important tasks in parallel; primarily it acts as an efficient anchoring group to me…

The joint adverse effects of aged nanoscale plastic debris and their co-occurring benzo[α]pyrene in freshwater mussel (Anodonta anatina)

2021

Although the presence of small-scale plastics, including nanoscale plastic debris (NPD, size1 μm), is expected in the environment, our understanding of their potential uptake and biodistribution in organisms is still limited. This mostly is because of the limitations in analytical techniques to characterize NPD in organisms' bodies. Moreover, it is still debatable whether aged NPD can sorb and transfer chemicals into organisms. Here, we apply iron oxide-doped polystyrene nanoparticles (Fe-PS NPs) of 270 nm size to quantify the uptake and biodistribution of NPD in freshwater mussels (Anodonta anatina). The Fe-PS NPs were, first, oxidized using heat-activated potassium persulfate treatments t…

Multifunctional Cationic PeptoStars as siRNA Carrier: Influence of Architecture and Histidine Modification on Knockdown Potential.

2019

RNA interference provides enormous potential for the treatment of several diseases, including cancer. Nevertheless, successful therapies based on siRNA require overcoming various challenges, such as poor pharmacokinetic characteristics of the small RNA molecule and inefficient cytosolic accumulation. In this respect, the development of functional siRNA carrier systems is a major task in biomedical research. To provide such a desired system, the synthesis of 3-arm and 6-arm PeptoStars is aimed for. The different branched polypept(o)idic architectures share a stealth-like polysarcosine corona for efficient shielding and a multifunctional polylysine core, which can be independently varied in s…