Soluble Unimolecular Polymer Nanoparticles by Crosslinking of Polyethylenimine with Isophthalaldehyde
Sueyuan Li,
James Edward Hanson
Issue:
Volume 7, Issue 4, December 2021
Pages:
50-56
Received:
16 September 2021
Accepted:
10 November 2021
Published:
19 November 2021
Abstract: Polyethylenimine (PEI) is a cationic polymer widely used in non-viral gene delivery systems and other polymer technologies. PEI with a MW of 25 kD was cross-linked in aqueous solution by the aromatic di-aldehyde isophthalaldehyde. This di-aldehyde cross-links PEI by forming stable imines with the primary amine groups in branched PEI. Cross-linking was evaluated at different concentrations of PEI using NMR, dynamic light scattering (DLS or QELS) and solvent extraction. It is demonstrated that isophthalaldehyde was able to cross-link PEI intramolecularly in solution near physiological pH resulting in the formation of unimolecular cross-linked nanoparticles. Proton NMR was used to examine the cross-linking reaction in-situ. The aldehyde resonance of isophthalaldehyde became broadened as cross-linking occurred. Organic-aqueous liquid-liquid extraction studies supported both that the cross-linking was intramolecular and that the cross-linked structures were stable to hydrolysis in water at neutral pH. As cross-linking occurred, the percentage of isophthalaldehyde that could be extracted from the solution was reduced. The molecular radii and aggregation behavior was monitored by QELS. The particle size of the polymer molecules in solution decreased with increased cross-linking, indicating the intra-molecular cross-linking between the PEI branches. These results clearly show that cross-linking of PEI with isophthalaldehyde creates soluble unimolecular polymer nanoparticles. These materials hold promise for a variety of applications in biotechnology.
Abstract: Polyethylenimine (PEI) is a cationic polymer widely used in non-viral gene delivery systems and other polymer technologies. PEI with a MW of 25 kD was cross-linked in aqueous solution by the aromatic di-aldehyde isophthalaldehyde. This di-aldehyde cross-links PEI by forming stable imines with the primary amine groups in branched PEI. Cross-linking ...
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Use of Novel and Environmental Friendly Natural Polymer and Its Alumina Nano-composite Synthesized from Rhynchophorus phoenicis in Waste Water Treatment
Osu Charles Ikenna,
Ugwu Henry Chimezie,
Iwuoha Godson Ndubuisi
Issue:
Volume 7, Issue 4, December 2021
Pages:
57-63
Received:
8 October 2021
Accepted:
29 October 2021
Published:
23 November 2021
Abstract: Novel and environmental friendly natural polymer and its Alumina nano-composite were synthesized from hard tissue of Rhynchophorus phoenicis gathered from palm trees at Omuoko community in Aluu, Ikwerre Local Government Area, Rivers state, Nigeria using standard methods. Dyes which are coloured organic compounds employed to put in colour onto cloth contaminate most of the water used. The natural polymer and its nano composite were used in Removal of dye from waste water. The investigation showed that chitosan (44.05 mg/g) has a lower adsorption capacity compared to alumina-chitosan composite (56.18 mg/g). This signifies that alumina-chitosan nano composite is a better adsorbent than chitosan. Batch adsorption tests of crystal violet dye confirmed that the adsorption process followed the pseudo-second-order kinetic model. The qe value ascertained for alumina-chitosan nanocomposite and chitosan for pseudo-second-order kinetic model, were 23.98 mg/g and 22.37 mg/g respectively. The optimum contact time for adsorption of crystal violet dye onto chitosan was attained at 40 minutes. Adsorption isotherms which are a very key tool for comprehending the circulation of the adsorbate on the adsorbent surface at equilibrium were used. Alumina-chitosan composite is better for the adsorption of crystal violet dye from wastewater than the chitosan. Going by the correlation coefficient, R2 values, the adsorption isotherm studies of crystal violet dye onto the chitosan and alumina-chitosan composite abided by the Langmuir isotherm model.
Abstract: Novel and environmental friendly natural polymer and its Alumina nano-composite were synthesized from hard tissue of Rhynchophorus phoenicis gathered from palm trees at Omuoko community in Aluu, Ikwerre Local Government Area, Rivers state, Nigeria using standard methods. Dyes which are coloured organic compounds employed to put in colour onto cloth...
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Evaluation of Self Healing Polymer and Rubber Composites: A Brief Review of Recent Achievements
Adolphe Edjenguele,
Elodie Njeumen Nkayem,
Njukeng Jetro Nkengafac
Issue:
Volume 7, Issue 4, December 2021
Pages:
64-72
Received:
5 July 2021
Accepted:
10 November 2021
Published:
24 November 2021
Abstract: Polymers contain extraordinary qualities, such as self-healing. Research and development of this form of polymer, which regenerates after injury, is an essential asset for artificial material lifetime and environmental sustainability. These polymers produced through polar interactions, hydrogen bonds, disulfide bonds, Diels Alders reactions and other types of interactions can totally recover their original qualities (high self healing effectiveness) at the molecular scale with repeatability without the need of chemicals. Self-healing capabilities may be introduced into a wide range of different materials, including concrete, ceramics, and metals, in addition to polymers and their composites. Despite extensive research in this field, mastering the self healing mechanism (intrinsic and extrinsic), characterization (spectroscopy and microscopy such as SEM, TEM to provide evidence of healing), and finding new sources of crosslinked fillers for polymers composites with high intrinsic self healing capabilities remain a significant difficulty. Microscope in the realm of creative product development, self-healing polymers and rubber composites have produced outstanding outcomes. Because of their exceptional excellent properties, such as strength/weight ratio, these materials have achieved great outcomes as well as corrosion resistance, fatigue resistance, specific heat resistance, specific modulus, high self healing capability. This article briefly reviews some important point of the mechanism, characterization, application and recent accomplishments of great self healing ability of rubber composites.
Abstract: Polymers contain extraordinary qualities, such as self-healing. Research and development of this form of polymer, which regenerates after injury, is an essential asset for artificial material lifetime and environmental sustainability. These polymers produced through polar interactions, hydrogen bonds, disulfide bonds, Diels Alders reactions and oth...
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Carbon Nanotube Reinforced Natural Fibers for Biodegradable Nanocomposites
Md. Johurul Islam,
Kamaruzzaman,
Mohammad Jellur Rahman,
M. M. Alam
Issue:
Volume 7, Issue 4, December 2021
Pages:
73-79
Received:
17 November 2021
Accepted:
6 December 2021
Published:
24 December 2021
Abstract: Natural fiber-reinforced nanocomposites (NFRCs) are proved as the best alternative for synthetic composites in view of cost and environmental effects. NFRCs have been produced from agro-waste such as banana tree fiber (BFs), because BF are strong, light-weight, and have smaller elongation. To improve the quality of BF, multiwall carbon nanotubes (MWCNTs) are used as reinforcing filler. MWCNTs are functionalized by an ecofriendly radio frequency oxygen plasma processing method. Cellulose nano-crystals (CNC) are extracted from BFs by double hydrolysis process and a simple dip-drying technique has been used to produce NFRCs. Field emission scanning electron micrographs and transmission electron microscopy conform the well functionalization of MWCNTs and also ensure homogeneous incorporation in the BF matrix. The composites continue thermally stable corresponding to BFs. Mechanical strength of the NFRCs are improved owing to the incorporation of MWCNTs. Functional groups in the BFs, CNC and NFRCs are investigated by Fourier transform infrared spectroscopy. The current density of the sample is increased 1000 times than the raw fibers and conductivity increases up to 17 Sm-1, which increases with temperature under the applied voltage 100 V and shows the linier characterization. Therefore, these light-weight biodegradable NFRCs encourage its ability as cost effective industrial conductive composite as usable in electronic devices.
Abstract: Natural fiber-reinforced nanocomposites (NFRCs) are proved as the best alternative for synthetic composites in view of cost and environmental effects. NFRCs have been produced from agro-waste such as banana tree fiber (BFs), because BF are strong, light-weight, and have smaller elongation. To improve the quality of BF, multiwall carbon nanotubes (M...
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