Characterization of the Antibacterial Activity of an SiO2 Nanoparticular Coating to Prevent Bacterial Contamination in Blood Products

Technological innovations and quality control processes within blood supply organizations have significantly improved blood safety for both donors and recipients. Nevertheless, the risk of transfusion-transmitted infection remains non-negligible. Applying a nanoparticular, antibacterial coating at the surface of medical devices is a promising strategy to prevent the spread of infections. In this study, we characterized the antibacterial activity of an SiO2 nanoparticular coating (i.e., the “Medical Antibacterial and Antiadhesive Coating” [MAAC]) applied on relevant polymeric materials (PM) used in the biomedical field. Electron microscopy revealed a smoother surface for the MAAC-treated PM compared to the reference, suggesting antiadhesive properties. The antibacterial activity was tested against selected Gram-positive and Gram-negative bacteria in accordance with ISO 22196. Bacterial growth was significantly reduced for the MAAC-treated PVC, plasticized PVC, polyurethane and silicone (90–99.999%) in which antibacterial activity of ≥1 log reduction was reached for all bacterial strains tested. Cytotoxicity was evaluated following ISO 10993-5 guidelines and L929 cell viability was calculated at ≥90% in the presence of MAAC. This study demonstrates that the MAAC could prevent bacterial contamination as demonstrated by the ISO 22196 tests, while further work needs to be done to improve the coating processability and effectiveness of more complex matrices.

Ductile crack initiation and growth on a plasticized Polyvinylchloride during air bag deployment

With the goal of ensuring the security of passengers for automotive industry, the present work addresses the ductile fracture process of plasticized PVC. Dedicated clamped single edge notch bending (SENB) specimens were used to characterize the mechanisms of crack initiation and propagation for the studied material. The exploitation of the experimental database associated with finite element simulation of the crack propagation allowed, on the one hand, the calibration factor η p of this specific SENB specimen to be established, as a function of the crack depth ratio. On the other hand, the fracture toughness of the studied plasticized PVC was estimated to be 10.8 kJ/m 2 , value which was close to that reported in the literature for modified PVC. By using this fracture toughness value, a methodology aiming at the prediction of ductile crack initiation of the PVC skin integrated into a real dashboard (full scale test) was proposed.

Combining Renewable Eleostearic Acid and Eugenol To Fabricate Sustainable Plasticizer and Its Effect of Plasticizing on PVC

The recent studies on sustainable plasticizer mainly focus on raw material source, synthesis method and plasticization, but the effect of chemical functional groups (epoxy group and ester group) of sustainable plasticizer on compatibility and thermal stability of plasticized polyvinyl chlorid (PVC) materials has been ignored. In this study, we synthesized two kinds of sustainable plasticizer, eleostearic acid eugenol ester(EAEE) and epoxidized EAEE. PVC films plasticized with EAEE were investigated and compared with epoxidized EAEE. PVC plasticized with epoxidized EAEE showed more flexible and thermal stability than EAEE. More hydrogen bonds were formed between PVC chains and epoxidized EAEE than that of PVC chains and EAEE, which caused the that epoxidized EAEE played more efficient plasticizing effect on PVC than EAEE. Epoxidized EAEE containing the flexible alkane chains and polar group (ester groups and epoxy groups) has stronger intermolecular interaction force than EAEE, causing homogeneous and smooth surface of plasticized PVC films.

Localized Deep and Shallow Traps of α-Peaks from Thermally Stimulated Current (TSC) Measurement on Thermoplastic Polymers

In this paper, trap levels around the glass transition temperature (Tg) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the Tg for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at Tmax = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, Ea of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.

Synthesis of biomass based plasticizer from linoleic acid and cardanol for preparing durable PVC material

In this paper, we synthesized a kind of bio-based plasticizer epoxidized linoleic acid cardanol ester(ELCE) from cardanol and linoleic acid. Its chemical structure was characterized with FT-IR and 1H NMR. Polyvinyl chloride(PVC) blends plasticized with ELCE were prepared via thermoplastic blending with torque rheometer. The performance including torque, mechanical property, thermal stability, plasticizing property and migration resistance of plasticized PVC blends were investigated and compared with plasticized PVC blends with commercial plasticizer dioctyl phthalate(DOP). The results showed that ELCE improved thermal stability of PVC blends. ELCE played more excellent plasticizing effect on PVC blends than DOP. The better solvent extraction resistance and volatile resistance of ELCE make it impossible to completely replace DOP in PVC products.

The Epoxidized Vietnam Rubber Seed Oil as a Secondary Plasticizer/Thermal Stabilizer in PVC Processing

The epoxidized rubber seed oil (EeRSO) was a mixture of epoxidized triglyceride, and epoxidized methyl ester of free fatty acids was used as a secondary plasticizer for PVC. An increase in tensile properties was observed by substituting the 10 phr DOP plasticizer with the EeRSO in PVC formulation. A leaching test was performed in five media to evaluate the plasticizing effect. The sample weight increased slightly after soaking in water and 30 wt.% acetic solution, decreased slightly in 10 wt.% KOH solution, and reduced sharply and strongly in sunflower oil and n-hexane. The 10 phr EeRSO in PVC formulation has presented an improvement in migration, volatilization characteristics, and thermal property of PVC. After 72 hours of soaking in n-hexane, the shore A hardness of the EeRSO plasticized PVC sample increased by 14.5% while the PVC sample without EeRSO was blistered and its shore A hardness could not be measured. This was the clearest evidence for the positive effect of EeRSO as a secondary plasticizer. The morphology of the fractured surface of the samples after immersing in n-hexane was studied by using scanning electron microscopy. Thermogravimetric analysis showed the role of EeRSO in significant improvement in thermal stability. In general, EeRSO not only acts as a primary plasticizer to improve the migration, extraction, and volatilization characteristics but also contributes to the thermal stability of PVC.

Compact NMR Spectroscopy for Low-Cost Identification and Quantification of PVC Plasticizers

Polyvinyl chloride (PVC), one of the most important polymer materials nowadays, has a large variety of formulations through the addition of various plasticizers to meet the property requirements of the different fields of applications. Routine analytical methods able to identify plasticizers and quantify their amount inside a PVC product with a high analysis throughput would promote an improved understanding of their impact on the macroscopic properties and the possible health and environmental risks associated with plasticizer leaching. In this context, a new approach to identify and quantify plasticizers employed in PVC commodities using low-field NMR spectroscopy and an appropriate non-deuterated solvent is introduced. The proposed method allows a low-cost, fast, and simple identification of the different plasticizers, even in the presence of a strong solvent signal. Plasticizer concentrations below 2 mg mL−1 in solution corresponding to 3 wt% in a PVC product can be quantified in just 1 min. The reliability of the proposed method is tested by comparison with results obtained under the same experimental conditions but using deuterated solvents. Additionally, the type and content of plasticizer in plasticized PVC samples were determined following an extraction procedure. Furthermore, possible ways to further decrease the quantification limit are discussed.

THERMO- AND LIGHT STABILIZING ACTIVITY OF VINYLOXYCLOPROPANE ADDUCTS WITH THIOLS IN THE COMPOSITIONS BASED ON PVC

During exploitation of PVC products, the negative impact of high temperatures and light, and also the destructive influence of various microorganisms, leads to the deterioration of physical-mechanical properties and change of products painting. For prevention of the dehydrochlorination process of PVC, it is necessary to use the effective complex stabilizers, including biostabilizers, differing with their high processability and simultaneously possessing biocidal properties. In this work the results of investigations of influence of the synthesized sulphur-containing epoxycyclopropanes as stabilizing additives for prevention of the dehydrochlorination process of the compositions based on plasticized PVC have been presented. The influence of these compounds as co-stabilizers in the composition of complex stabilizers – stearates Ca (CaSt2) and Zn (ZnSt2) on thermo- and light stability of PVCcompositions and also on their physical-mechanical and exploitation indices has been studied. It has been established the synthesized epoxy- and cyclopropane-containing mono- and disulphides jointly with stearic acid salts form the synergic mixtures, which can improve the physical-mechanical properties of PVC compositions, their thermal and light stability.