Kaolinite-Cellulose based Nano–Composites and Applications

Current synthesis and characterization techniques for clay-based polymer nano-composites and its biomedical applications: A review

In this study, the amino propyl trimethoxy silane was used for the surface modification of silica, and the modified silica was adsorbed to surface of clay/silica (SiO2 : Clay = 4:1 and 2:1) and the clay/silica was adsorbed by the surfactant. Also, we used Dimethyldistearylammonium chloride (DMDSAC) and Dodecyltriphenylphosphonium (DTPPB) surfactant to modify clay/silica. Then we prepared the Epoxy/clay/silica nanocomposites and Epoxy/clay/silica/DOPO composites. In FTIR analysis, we found the Si-O-Si bond of silica and amino silane at 1114 cm-1, the N-H absorption peak emerges at 1564 cm-1, and the C-H absorption peak occurs at 2858 cm-1, 2926 cm-1. In DSC analysis, we found the glass transition temperature of nanocomposites were 152.0 oC and 150.1 oC, when the content of clay were 1.2 wt % and 2.0 wt% respectively. When the temperature of post cure in preparing nanocomposites reaches 200 oC, the glass transition temperature of nanocomposites were 178.0 oC and 170.3 oC. Therefore, increasing the temperature of post cure can lead the nanocomposite crosslinked completely and the segmental mobility of epoxy polymer decreased with the consequence of higher glass transition temperatures. In TEM studies, we found the d-spacing of clay galleries were enlarged by silica particles and clay platelets were highly exfoliated. When the clay in nanocomposites reached 0.2 wt %, the d-spacing of clay was 30 ~ 40 nm. When the clay in the nanocomposites reached to 1.2 wt % and 2.0 wt %, the d-spacing of clay was 30 nm and 20 nm, respectively.We found, in the nanocomposites containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) flame retardant, when the content of clay were 1.2 wt % and 1.9 wt %, the clay aggregate more and the d-spacing was 20 and 15 nm respectively. In the analysis of TGA, the thermal decomposition temperature of nanocomposites at TG = 95 % decreases with the increase of DOPO, the char yield is high at 800 oC. In LOI studies, the LOI of pure epoxy is 26.3. When adding the DOPO in the pure epoxy, the LOI is 28.3. The LOI of nanocomposites increases to 32.0 when the clay in the nanocomposites reaches 1.9 wt %. When the amount of clay in the nanocomposites increases to 1.8 wt %, the LOI of nanocomposites is 30.5. It is suggest that nanocomposites with clay can improve the flame retardancy and the in corporation of silica enhances the contact surface area between clay and epoxy resin and hence becomes more flame retardant. In the analysis of DMA, when the post cure temperature of nanocomposites is 150 oC, the E’ value increase from 19.2 % to 61.3 % at 35 oC. When the post cure temperature of nanocomposites is 200 oC, the E’ value increased from 1.8 % to 43.5 % at 35 oC. With the addition of the DOPO in the nanocomposites under the clay content from 0.4 wt % to 1.9 wt %, the E’ value increases from 8.8 % to 27.4 % at 35 oC.

With the aggravation of fire and smoke pollution, it is urgent to develop green, lower-cost and high-performance Foamed Wood–Plastic Composite (FWPC) to meet the standards of antistatic and flame retardant in practical application. Therefore, the flame retardant and antistatic FWPCs were prepared by compression molding in this study. High-density polyethylene (PE-HD) and Salix wood flour were used as main raw materials, and azodicarbonamide (AC) was used as foaming agent; Nano-carbon black (Nano-CB) was used as antistatic filler, and ammonium polyphosphate (APP) and zinc borate (ZB) were used as flame retardants. The static bending strength and elastic modulus of FWPC-20 were up to 30.01 MPa and 2636 MPa, respectively, which can meet the commercial application of wood–plastic decorative board. The logarithm of surface resistivity and volume resistivity of FWPC-20 was kept at eight, indicating that it has antistatic effect. The residual carbon rate of FWPC-20 increased to 38.58% at 800 °C, indicating that FWPC had high thermal stability. The minimum heat release rate of FWPC-20 was 226.75 kw/m2, and the average heat release rate was 110.53 kw/m2. The total heat release was 66.96 MJ/m2, and the Limit Oxygen Index was 27.3%, which indicated that FWPC-20 had flame retardant and smoke suppression effects. This study provides a low-cost and simple method for the design of flame retardant, antistatic and high-performance FWPC, and has broad application prospects in the fields of packaging and construction.

Organic and inorganic contaminants polluting global water resources are concerning the world. Generally, being non-biodegradable synthetic and/or highly soluble in water, pollutants get easily mobilized in the environment. Their interaction with and accumulation in environment has adverse effects on ecosystems and human health.Deterioration of environment thanks to human activities is increasing daily which results in the discharge of toxic effluents, like pesticides, heavy metals and toxic dyes into environment, causing serious health problems to humans and pollution to environment. Nanocomposites have wide applications in different fields like air purification, wastewater treatment via heavy metal removal, soil improvement, fertilizers delivery systems, food packaging and flame retardency. Nanocomposite composition gives a large surface area with special properties. Lately nanocomposite structures are employed to purify water, develop fertilizer retention in soil, and enhances plant growth resulting in agricultural development, food packaging and flame retardancy. Properties of these nanocomposites rely upon both the properties of their constituents and also the combination between polymer/nano-filler.This chapter covers the advances on nanocomposites aimed at water decontamination through remediation of metal ions and synthetic organic chemicals, especially dyes, from wastewater.KeywordsNanocompositesMetal uptakeAntimicrobial activityDelivery system

This study is aimed to prepare and investigate the optical, electrical and antibacterial activity of the environmentally friendly (green) chitosan (Cs)/silver nanocomposites. TEM demonstrated that AgNPs have a spherical shape with particle size ranged from 3 nm to 25 nm. UV analysis spectra of Cs and Cs/Ag nanocomposites showed that, increasing the content of AgNPs led to a noticeable increase in the values of Urbach energy (E U ) and a dramatic decrease in both the indirect (E ig ) and direct (E dg ) optical bandgap energies. It is found that (E ig ) and (E dg ) are decreased from (4.72/5.31 eV) to (2.47/4.19 eV). The formation of the AgNPs is verified by the existence of surface plasmon resonance (SPR) peak at ∼ (421–450) nm. Wemple-DiDomenico and Sellmeier oscillator models are employed and displayed a clear enrichment in the dispersion energy (E d ) and oscillator energy (E 0) as well as the linear and nonlinear optical parameters of Cs. It is observed that the linear (χ(1)) and nonlinear (χ(3) and n2) parameters are enhanced from 0.083, 0.868 × 10−14 and 1.584 × 10−12 to 0.153, 9.762 × 10−14 and 4.088 × 10−12. The novel results in our study nominate Cs/Ag nanocomposites for applications in linear/nonlinear optical devices. AC conductivity behavior of Cs and Cs/Ag nanocomposites is analyzed based on Jonscher’s law and the analysis showed that the overlapping large polaron tunneling (OLPT) is the dominant conduction mechanism for our samples. It is clear that the values of dielectric constant (ε′) of Cs and Cs/Ag nanocomposites are higher confirming the presence of interface polarization (IP) relaxation. Moreover, it is found that the antibacterial activity of Cs against Gram-negative (P. aeruginosa) and Gram-positive (B. thuringiensis) bacteria is found to be enhanced with increasing the content of Ag NPs. These results suggested that Cs/Ag nanocomposites will be good source for preparing bio-nanocomposites for use in many biomedical and industrial applications.

Sodium‐alginate‐based aerogels possess wide prospects in the fields of packaging, aerospace, industrial construction and transportation because of their environmental compatibility and thermal insulation, but it is still a challenge to obtain a sodium alginate‐based aerogel with high flame retardancy and good thermal insulation. Herein, a sodium‐alginate‐based aerogel with high flame retardancy, thermal insulation and good hydrophobic properties was prepared by two‐step crosslinking strategy of phytic acid and metal ions and liquid phase deposition of trans‐cinnamic acid. As a result, the prepared SA/PA Mn+ aerogels obtained excellent flame retardancy (UL‐94 V‐0, LOI 50.1%) and rapid self‐extinguishing, and SA/PA Mn+ aerogels obtained good hydrophobic ability (CA = 134.2°). In addition, the mechanical properties of SA/PA Mn+ aerogels have also been improved, the compressive modulus increased from 0.66 to 6.37 MPa, and the specific modulus increased from 15.7 to 140.2 MPa cm −3 g−1. This research broadens the application of bio‐based flame‐retardant aerogels in the fields of packaging, aerospace, industrial construction and transportation.

No one wants their bed, couch, chair, computer, or TV to catch on fire. “If an ordinary upholstered chair in your home gets ignited, it can essentially take your whole house down,” says Richard Gann, a senior research scientist at the U.S. National Institute of Standards and Technology’s (NIST) Building and Fire Research Laboratory. The most flammable part of a mattress or couch is its plastic polyurethane foam cushioning, he explains. Once a fire gets through a chair or mattress’s fabric covering and into this cushioning, it can start a catastrophic reaction that quickly leads to “flashover,” in which nearly everything combustible inside a room ignites simultaneously. Until very recently, brominated flame retardants, especially polybrominated diphenyl ethers (PBDEs), were one of the main materials used to reduce the speed with which the plastic components of consumer goods including beds, couches, chairs, and electronics could be consumed by fire. However, growing evidence shows that PBDE compounds are escaping from the products they protect and making their way into the products’ users. Moreover, the chemicals may disrupt human thyroid hormone functioning and cause other health effects, prompting many nations to ban or suspend their use in new consumer goods. [For more information on the health effects of PBDEs, see “Unwelcome Guest: PBDEs in Indoor Dust, p. A202 this issue.] Although bromine- and chlorine-containing flame retardants are still used in some products, the need for new alternatives is being driven by a confluence of policy, standards, and pressure from environmental groups. Europe banned the use of two formulations, PBDE pentaBDE and octaBDE, in 2004, the same year they were withdrawn from the North American market. A third compound, decaBDE, was banned 1 April 2008 by the European Court of Justice. Stateside, Maine has banned the use of decaBDE, the only PBDE still on the market in North America, in mattresses and residential upholstered furniture produced and sold in that state, and will extend the ban to electronics in 2010. Washington prohibits the use of decaBDE in mattresses and sets a process for a future ban in furniture and electronics if the state can identify a safer and feasible alternative that meets fire safety standards. Asian countries and other U.S. states have similar legislation in the works. “Instead of adding new fire retardant chemicals that ultimately may be shown to cause health problems, we should be asking whether we need to use these chemicals or if there are other ways to achieve equivalent fire safety,” contends Arlene Blum, a biophysical chemist and visiting scholar at the University of California, Berkeley. “So many of the chemicals we have banned in the past were flame retardants—think about asbestos, polychlorinated biphenyls, polybrominated biphenyls, tris(2,3-dibromopropyl) phosphate, PBDEs—[and] they all ended up in the environment and in people,” she points out. “We need to think carefully about adding these sorts of chemicals to consumer products before there is adequate health information.”

The facile fabrication of a bioderived flame retardant (marked as ATMP‐A) via ionic exchange between adenine and amino trimethylene phosphonic acid was reported in the present work. The incorporation of ATMP‐A endows the poly lactic acid (PLA)/poly butylene adipate‐co‐terephthalate (PBAT)/thermoplastic starch (TPS) ternary blends with improved fire safety without negatively affecting the biodegradability. The PLA/PBAT/TPS blend containing 18 wt% ATMP‐A alone achieves a UL‐94 V‐0 rating with a higher LOI value (28%). Meanwhile, its peak of the heat release rate and total heat release are reduced by 60.5% and 34.1% as compared with the PLA/PBAT/TPS ternary blend, respectively. Such excellent flame retardancy is mainly attributed to the formation of the intumescent flame retardant system in which ATMP‐A acts as both acid and gas sources together with TPS as a natural carbon source. Based on the analysis of the volatile gases and the char residues, a possible flame retardant mechanism including gas phase and condensed phase is proposed. This work provides a novel and effective idea for improving the fireproof performance of PLA/PBAT/TPS blends and will broaden its practical application fields, such as, agricultural film and packaging fields.

Characterization of anti bacterial biocomposite films based on poly lactic acid and prosopis juliflora bark powder

Today, modified cotton materials have become an important aspect of man’s life since they can be utilized in various advanced applications. Among them, superhydrophobicity and flame retardancy are the most crucial improvements for advanced industrial physical applications. These are characterized by enhancement of the physical resistance of cotton textiles against water and fire, respectively, which are the most common physical conditions that favor the degradation of natural materials. This hence provides safety to human life and his property. The present chapter, therefore, summarizes the research progress of cotton fabrics modified for advanced physical applications, highlighting the different chemical agents used and their binding interaction, imparting techniques, the quality of the modified textiles, and the potential fields of usage.KeywordsModified cottonSuperhydrophobicityFlame retardancyChemical agents

Synergy effect between quaternary phosphonium ionic liquid and ammonium polyphosphate toward flame retardant PLA with improved toughness

Poly(L-lactic acid) (PLLA) is a thermoplastic material with complete degradability, high biocompatibility and excellent mechanical properties. It can replace petroleum-based polymers are currently being used in the fields of packaging, agriculture, textiles, medical and so on. However, PLLA’s extremely flammability greatly limits its wider application. An bio-based flame retardant L-APP/PLLA composites was prepared by melt blending of the L-APP and PLLA. The morphology, impact properties, thermal properties and flame retardant properties of composites were investigated by field emission scanning electron microscope (SEM), impact tester, differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), limiting oxygen indexer (LOI) and horizontalvertical burning tester. The results showed that the degree of crystallization (Xc) and LOI of L-APP/PLLA composites increased as increasing of L-APP content. What’s more, the impact strength first increased and then decreased, the glass transition temperature (Tg) and melting temperature (Tm) do not changed significantly. The impact strength of composites was 9.1 kJ/m2 at a 5 wt% loading for L-APP, which was the highest level. When the content of L-APP was 20%, the LOI was 30.8%, the Xc was 42.3% and the UL-94 level was V-0. This research can promote the value-added utilization of lignin and the application of PLLA in the fields of flame retardant materials.

Integration of wastewater treatment units and optimization of waste residue pyrolysis conditions in the brominated phenol flame retardant industry

3 - Epoxy resin based hybrid polymer composites

Polyvinyl alcohol (PVA) has been widely used in the fields of medical, food and packaging due to its excellent biocompatibility, good fiber-forming and film-forming properties. However, the high flammability of PVA has greatly limited its wider applications. The flame-retardant PVA was prepared by melt blending of a bio-based flame retardant (prepared from lignin, phosphoric acid and carbamide) with thermoplastic PVA (TPVA). The chemical structure, morphology, thermal properties, mechanical properties, fire property and fluidity of this flame retardant PVA were investigated by Fourier transform infrared spectrometer(FTIR), field emission scanning electron microscope(SEM), thermogravimetric analyzer(TGA), impact tester, universal testing machine, horizontal-vertical burning tester, limiting oxygen indexer(LOI) and melt flow rate meter(MFR). The results showed that the prepared flame retardant had good compatibility with the PVA substrate; The impact strength, melt flow rate, fire property and char residue of this PVA material increased with the content of bio-based flame retardant. When the content of flame retardant was of 20%, the five indices including impact strength, melt flow rate, UL-94 level, LOI and char residual were 11.3 KJ/m2, 21.2 g/10 min, V-0 UL-94 level, 33.1%, and 19.2%, respectively. This research can promote the high-value utilization of lignin and the application of PVA in the fields of fire protection.