scholarly journals Antimicrobial Property of Polypropylene Composites and Functionalized Copper Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1694
Author(s):  
Noemi Jardón-Maximino ◽  
Gregorio Cadenas-Pliego ◽  
Carlos A. Ávila-Orta ◽  
Víctor Eduardo Comparán-Padilla ◽  
Luis E. Lugo-Uribe ◽  
...  

Copper nanoparticles (CuNPs) functionalized with polyethyleneimine (PEI) and 4-aminobutyric acid (GABA) were used to obtain composites with isotactic polypropylene (iPP). The iPP/CuNPs composites were prepared at copper concentrations of 0.25–5.0 wt % by melt mixing, no evidence of oxidation of the CuNP was observed. Furthermore, the release of copper ions from iPP/CuNPs composites in an aqueous medium was studied. The release of cupric ions was higher in the composites with 2.5 and 5.0 wt %. These composites showed excellent antibacterial activity (AA) toward Pseudomona aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). The incorporation of CuNP into the iPP polymeric matrix slightly decreased the thermal stability of the composite material but improved the crystallinity and the storage modulus. This evidence suggests that CuNPs could work as nucleating agents in the iPP crystallization process. The iPP/CuNPs composites presented better AA properties compared to similar composites reported previously. This behavior indicates that the new materials have great potential to be used in various applications that can be explored in the future.

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shibin Nie ◽  
Chi Zhang ◽  
Chao Peng ◽  
De-yi Wang ◽  
Daowei Ding ◽  
...  

A char forming agent (CFA) and silica-gel microencapsulated ammonium polyphosphate (Si-MCAPP) were selected to form novel intumescent flame retardant system to prepare flame retardant polypropylene (PP) composites, and then the influences of nanoporous nickel phosphates (NiP) on the thermal and flame retardant properties of flame retardant PP composites were studied by the real time FTIR (RTFTIR) spectra, limited oxygen index (LOI) test, and the scanning electron microscopy. RTFTIR shows the addition of NiP can improve the thermal stability of flame retardant PP composites. LOI test shows LOI value is increased with the increase of the content of NiP, and the optimized concentration of NiP is 1.0%. Furthermore, smoke toxicity of the novel flame retardant PP composites was studied by mice experiment. The upper limit of the no death smoke concentration of the composite is 12.37 mg/L.


2019 ◽  
Vol 107 (6) ◽  
pp. 523-529 ◽  
Author(s):  
Mohamad Bekhit ◽  
Asmaa Sobhy ◽  
Zakaria I. Ali ◽  
Sameh M. Gafar

Abstract A novel high-dose dosimeter based on γ radiation reduction of copper ions and formation of copper metal inside polymer matrix were investigated. γ radiation induced synthesis of copper nanoparticles (CuNPs) in poly vinyl alcohol films were studied by UV-Visible Spectrophotometer, X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The optical absorption spectra showed that the Cu/PVA nanocomposite films have surface plasmon resonance (SPR) of copper nanoparticles which depending on irradiation doses. Upon γ irradiation these films turns its color from faint blue to deep reddish brown depending on metal ion concentration. The XRD pattern and FTIR spectrum confirm the formation of the CuNPs. The response of Cu/PVA nanocomposite dosimeters depends on both the irradiation doses and concentration of copper precursor. The dose range for these films was from 50 to 650 kGy, revealing its important applications for high dose dosimetry. Cu/PVA nanocomposites films exhibit good post-irradiation stability in dark and light.


2020 ◽  
pp. 002199832096053 ◽  
Author(s):  
Noelle C Zanini ◽  
Rennan FS Barbosa ◽  
Alana G de Souza ◽  
Derval S Rosa ◽  
Daniella R Mulinari

Australian palm residues are generated by palm heart industry in large quantities and are considered an underused material with a composition rich in lignocellulosic structures. This residue is generally utilized as briquettes for energy or sheep feed; however, few works investigate this residue as composite fillers. This work aimed to revalue Australian palm residues (PR) by preparing polypropylene composites through melt mixing, using different fiber contents (0, 5, 10, 20, and 30 wt%), and evaluate the statistical influence of fibers (residues) alkali treatment (MPR) in composites mechanical properties. PR and MPR were evaluated by FTIR, XRD, SEM, TGA, and composites were assessed using thermal and mechanical analysis, in which ANOVA statistical analysis was applied. The residues addition increased the mechanical properties and their treatment enhanced the stiffness of the composites compared to pristine PP. However, ANOVA demonstrated that at low residues contents, surface treatment does not increase fiber-matrix interactions effectively, then tensile properties were statistically similar to PP. Considering tensile properties, 20% MPR showed statistically distinct properties, with significative enhancements; no filler contents dependence was verified. Flexural properties were more sensitive to residue loading, and composites with 30% PR and MPR presented superior mechanical performance. This difference is associated with a higher sensitivity of tensile stress towards fiber-matrix interactions, which was improved with fiber treatment. Also, the residues content and treatment influenced the composites' thermal stability, with better results for PP-MPR. Results indicate that palm residue is an excellent filler for improving composites' thermal and mechanical properties, with a greener character.


2019 ◽  
Vol 91 (6) ◽  
pp. 967-982 ◽  
Author(s):  
Halina Kaczmarek ◽  
Marta Chylińska ◽  
Ewa Klimiec ◽  
Bogusław Królikowski ◽  
Grzegorz Sionkowski ◽  
...  

Abstract PP-based composites with two mineral fillers (perlite or glass beads) were manufactured by extrusion, and then subjected to orientation in a ratio of 3:1. Electrets were obtained in the polarization process under the influence of a constant electric field. Sample morphology was tested by SEM whereas the crystallinity was determined by XRD. Mechanical strength and thermal stability of composites was studied by tensile tests and thermogravimetric analysis, respectively. The piezoelectric characteristics were appointed by measurement of the electrical charge and current voltage in the polarized samples. The dependence of thermally stimulated depolarized current (TSDC) on temperature was also investigated. The piezoelectric coefficient (d33), the electret stability over time as well as activation energy of depolarization process have been determined. It was found that low filler content (i.e. 2.5 and 5 wt.% of glass beads and perlite, respectively) significantly improve piezoelectric properties of isotactic polypropylene (i-PP).


2015 ◽  
Vol 05 (03) ◽  
pp. 1550018 ◽  
Author(s):  
P. Thomas ◽  
B. S. Dakshayini ◽  
H. S. Kushwaha ◽  
Rahul Vaish

Composites of poly(methyl methacrylate) (PMMA) and [Formula: see text] (STMO) were fabricated via melt mixing followed by hot pressing technique. These were characterized using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), thermo mechanical analysis (TMA) and impedance analyser for their structural, thermal and dielectric properties. The coefficient of thermal expansion (CTE) was measured between 40°C and 100°C for pure PMMA is 115.2 ppm/°C, which was decreased to 78.58 ppm/°C when the STMO content was increased to 50 wt.% in PMMA. There was no difference in the glass transition ([Formula: see text]) temperature of the PMMA polymer and their composites. However, the FTIR analysis indicated possible interaction between the PMMA and STMO. The density and the hardness were increased as the STMO content increased in the PMMA matrix. Permittivity was found to be as high as 30.9 at 100 Hz for the PMMA+STMO-50 wt.% composites, indicating the possibility of using these materials for capacitor applications. The thermal stability of polymer was enhanced by incorporation of STMO fillers.


2015 ◽  
Vol 668 ◽  
pp. 28-38 ◽  
Author(s):  
Claudio Roberto Passatore ◽  
Alcides Lopes Leão ◽  
Derval dos Santos Rosa

The main objective of this investigation was to study the properties of composites of polypropylene (PP) containing different proportions (20, 40 and 60% wt%) of coir short fiber (natural vegetable fiber) without treatment of fibers, for use in products by injection with applications in the automotive industries, construction and other segments. Samples were prepared in a only stage using a high intensity thermokinetic mixer (K-Mixer). Additives were used in the mass fraction of 3 wt% compatibilizer (PP-g-MA), 2.2 wt% processing additive and 0.12 wt% thermal antioxidant. The composites were characterized by tensile test according to ASTM D638-10. The surface properties of the polymeric matrix with additives were studied by determining the contact angle (CA) in a sessile drop tensiometer and the carbonyl index (CI) by Fourier-transform infrared spectroscopy (FTIR). Thermal properties of the PP and the composition were evaluated by thermogravimetric test, and the interface of the fiber and the matrix in the composites were evaluated using images from scanning electron microscopy (SEM). The CA analysis showed that the PP matrix with additives has become less hydrophobic and the FTIR and the CI that there was a better stabilization of the PP with additives. There was an increase in thermal stability of the composites for all fiber content, which was up to 15 °C above PP for coir fiber composites. In the Young's modulus values showed that the inclusion of fibers reinforced the polymeric matrix and increased the stiffness of the composites, especially in composites containing 60% (wt%) in which the values were ~1.7 times greater than the polypropylene. Images of micrographs showed the interaction of the fiber in the matrix and that despite the hydrophilic character of the fibers and hydrophobic character of the PP, the composites showed non-homogeneous interfaces. These findings confirm the feasibility of using high level of coir fiber in polypropylene composites even without pretreatment of the fibers and the preparation of samples by injection.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Aminu Musa ◽  
Mansor B. Ahmad ◽  
Mohd Zobir Hussein ◽  
Saiman Mohd Izham ◽  
Kamyar Shameli ◽  
...  

A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by nanocrystalline cellulose (NCC) using different concentrations of copper salt in aqueous solution under atmospheric air. CuSO4·5H2O salt and hydrazine were used as metal ion precursor and reducing agent, respectively. Ascorbic acid and aqueous NaOH were also used as an antioxidant and a pH moderator, respectively. The number of CuNPs increased with increasing concentration of the precursor salt. The formation of copper nanoparticles stabilized by NCC (CuNPs@NCC) was investigated by UV-visible spectroscopy (UV-vis), where the surface absorption maximum was observed at 590 nm. X-ray diffraction (XRD) analysis showed that the CuNPs@NCC are of a face-centered cubic structure. Moreover, the morphology of the CuNPs@NCC was investigated using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM), which showed well-dispersed CuNPs with an average particle size less than 4 nm and the shape of CuNPs was found to be spherical. Energy dispersive X-ray spectroscope (EDS) also confirmed the presence of CuNPs on the NCC. The results demonstrate that the stability of CuNPs decreases with an increasing concentration of the copper ions.


2016 ◽  
Vol 857 ◽  
pp. 191-195 ◽  
Author(s):  
A. Nadiatul Husna ◽  
Bee Ying Lim ◽  
H. Salmah ◽  
Chun Hong Voon

Palm kernel shells (PKS) filled recycled high density polyethylene (rHDPE) biocomposites were produced using melt mixing. The biocomposites were prepared on Brabender Plasticorder at temperature of 185 °C and rotor speed of 50 rpm by varying filler loading (0 to 40 phr). In this study, the effect of PKS loading on rheological properties and thermal stability of rHDPE/PKS were investigated. Rheological study of the biocomposites was carried out by means of capillary rheometer under temperature of 190 °C, 200 °C and 210 °C. Thermal properties of biocomposites were studied by using thermo gravimetric analysis (TGA). The rheological results showed that the flowability of the composite increased with increasing temperature. Meanwhile, the result of TGA showed that at higher PKS loading, rHDPE/PKS biocomposites had lower total weight loss. The thermal stability of the biocomposites was reduced due to the addition of filler loading.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Rubén Sierra-Ávila ◽  
Marissa Pérez-Alvarez ◽  
Gregorio Cadenas-Pliego ◽  
Carlos Alberto Ávila-Orta ◽  
Rebeca Betancourt-Galindo ◽  
...  

The synthesis of copper nanoparticles was studied by wet chemical methods using copper sulfate pentahydrate (CuSO4·5H2O) and nitrogen ligands allylamine (AAm) and polyallylamine (PAAm) as stabilizers. The results suggest that the use of these ligands leads to the exclusive formation of metallic copper nanoparticles (Cu-NPs). The use of partially crosslinked polyallylamine (PAAmc) leads to nanoparticles (NPs) with low yields and high coating content, while linear PAAm leads to NPs with high yields and low coating content. The chemical composition of the particles was determined by XRD and average particle diameters were determined by the Debye-Scherrer equation. TGA analysis provided evidence of the content and thermal stability of the coating on the nanoparticles and PAAm. The morphology, particle size distribution, and presence of PAAm coating were observed through TEM. The use of AAm in the synthesis of NPs could be a good alternative to reduce costs. By using TGA, TEM, and DSC techniques, it was determined that synthesized NPs with AAm presented a coating with similar characteristics to NPs with PAAm, suggesting that AAm underwent polymerization during the synthesis.


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