Starch Cellulose Acetate Research Articles

Sustainable Cross-Linkers for the Synthesis of Cellulose-Based Aerogels: Research and Application

Cellulose aerogels with polyester resin as cross-linkers have attracted much attention. This study describes the route to produce a fully bio-based aerogel with high added value from waste paper and starch, cellulose acetate and starch–cellulose acetate mixture as cross-linkers for oil adsorption, instead of the environmentally harmful polyester resin. The manufacturing process is simple, sustainable and cost-efficient, without releasing harmful by-products into the environment. The effects of different cross-linkers on the oil adsorption, dynamic oil retention, reusability and morphology of the aerogels were studied in detail. Experimental results show that these environmentally friendly recycled aerogels have a very low density, i.e., —0.0110–0.0209 g cm−3, and highly porous structures, with a porosity of 96.74–99.18%. The synthesized hydrophobic aerogels showed contact angles of ∼124–129°. The compression moduli are lower than that of an aerogel with polyester as a cross-linker, but the compression modulus of the mixture of starch and cellulose acetate especially shows a higher value than expected. The sorption capacity of the aerogels with bio-based cross-linkers was significantly increased compared to the aerogels with polyester; it is now up to 56 times their own weight. The aerogels also have good oil-retention properties.

A preliminary study of bioplastic composites based on carbon materials from paper waste and corn waste

Waste materials continue to increase and have become a major problem in many countries. In this work,waste was recycled to form bioplastic composites. The study focused on the bioplastic (starch-cellulose acetate)-carbon material composites. The Graphene Oxide (GO) and Carbon-dots (CD) were chosen as filler materials. The physical properties of these bioplastics were investigated using tensile test, water uptake test and biodegradation test. Results showed that the addition of GO and CD reduced the tensile strength and elongation. It was also found that the water uptake decreased while the biodegradation rate increased with GO or CD addition. The interaction between the bioplastic starch-cellulose acetate matrix and the carbon materials as fillers can change the mechanical properties of the bioplastics. The carbon materials fill in the pores in bioplastics and make the bioplastic more waterproof and their hydrophilic properties attract water faster and help the activation of microbial activity during the biodegradation.

Assessment of the in vitro controlled release for some polymeric nanocomposites loaded with different drugs

Synthesized starch cellulose acetate coacrylate (SCACA)/ Sodium bentonite modified Tween-80 (MSB) nanocomposites holding anticancer drugs like 5-fluorouracil (5-FU), Doxorubicin hydrochloride (DOX), and Chlorambucil (CA) as controlled release systems were evaluated and assessment as antiproliferative activity towards breast cancer cell lines, and antimicrobial activity against some strains. The nanocomposites loaded drugs characterized by Zeta Potential, FTIR, SEM and TEM. The results indicated that no change in the chemical structures and physical properties of the drugs into the nanocomposites. The surface texture of the samples was homogenous and smooth with no evidence of aggregations after release and there were some pore like structure and cracks formed due to blooming of drug outside nanocomposites. The particle size diameter of the prepared polymer was found to be 73 ~ 79 nm. After holding Doxorubicin the particle size was from 18 to 24 nm , 5-fluorouracil from 15 to 18 nm and Chlorambucil was from 24 to 75 nm. The release of drug was measured spectrophotometrically. The values of drug released depend on the type and nature of drug as well as the environmental aqueous media. The release in alkaline and acidic media was more faster and higher than that in the neutral one. The invitro study results of anticancer drugs released from polymers placed inside the culture media, showed 5-FU was given an effective promising results compared to DOX and CA. The antimicrobial test revealed that, the released 5-FU gave the highest effect as antimicrobial against all tested strains followed by DOX and CA.

Evaluation of Synthesized Starch Cellulose Acetate Coacrylate and nanoclay holding drugs

5-fluorouracil (5-FU), doxorubicin (DOX), and chlorambucil (CA) are functional drugs to destroy cancer cells in individuals with different carcinoma. The slow release profile is an optimistic technique and controls the drug release over a long time. This study is based on the incorporation of the drug on the nano-sized clay into polymeric host-carrier. The polymeric material based on potato starch cellulose acetate compound copolymerized with the acrylic acid monomer (SCACA) by a free-radical mechanism. The main aim of the represented study is to increase the drug efficiency for long period stability and simultaneously modifying drug delivery technologies with nano-clay (modified sodium bentonite (MSB)). The prepared drug delivery carrier was characterized by Fourier transform infrared spectroscopy (FT-IR). The evaluation of equilibrium swelling ratios (Q) for the SCACA without and with modified bentonite (0.05 and 2%) depict that greater modified clay content gave the lower Q value of the prepared polymer. The release rate was investigated in aqueous media of different pH values and measured spectrophotometrically. It was found that the release rate depends on the pH of the aqueous media in addition to the content of clay used in the polymeric modification. The modified polymer/ nano-clay drug carrier has been also evaluated as an antiproliferative agent against human liver cancer cell line (HEPG2). The results show that, 5-FU gave the highest growth inhibition potency from 54:48% followed by CA which gave 37:46% , while DOX showed the lowest growth inhibition donated 41:29% for all days exposure . This may due to the release of 5- FU is more than CA and Dox., but all drugs have a promising results.

Structure and mechanical properties of 3D-printed cellulose tablets by fused deposition modeling

This paper evaluated corn starch/cellulose acetate (SCA) specimens 3D-printed by the fused deposition modeling (FDM) method. The influence of the printing parameters, nozzle temperature, and flow rate on the morphological and mechanical properties of the specimens was evaluated. Scanning electron microscopy (SEM) showed smooth surfaces on all the 3D-printed specimens. The fracture surface analysis revealed homogeneity and low porosity of the specimens printed at 230 °C and 90% flow rate. The flexural tests showed high values of the flexural modulus for the specimens printed at 240 °C and 80% flow rate, and the fatigue tests demonstrated that the 230-90 SCA specimens were resistant to successive cyclic loads.

Evaluation of controlled release PVC/PEG polymeric films containing 5-fluorouracil for long-term antitumor

The polymeric film based on polyvinyl chloride (PVC)/polyethylene glycol (PEG) and starch cellulose acetate (SCA) using trioctyltrimellitate (TOTM) as a plasticizer was prepared. It was found that PVC/PEG/TOTM (10/90/5) blend film containing 60% SCA has a good optimum mechanical property. The prepared polymer film was loaded with 5-fluorouracil (5-FU) as a traditional anticancer drug. The prepared polymer with and without the 5-FU drug was characterized by Fourier-transform infrared spectroscopy. The polymer carried 5-fluorouracil was examined as slow release drug through subjecting to aqueous media of varied pHs for different time periods. The release was measured spectrophotometrically. It was found that the release rate depends on the pH of the aqueous media. The release of the drug in the alkaline media was found to be faster and higher compared to the other media. Also, the sustained release of the drug was extended to about 60 days. The diffusion coefficient (D) of the released 5-FU carrier was determined, and the calculated values were found to be 4.595 × 10−5, 3.846 × 10−4 and 8.756 × 10−4 mm2/day in neutral, acidic and basic media, respectively, according to Higuch’s equation. The data obtained from the in vitro cytotoxic activity of the released 5-FU showed a sustained antiproliferative potency against human liver cancer cell line with different ratios for growth inhibition of cancer cells.

Influence of process parameters on microstructure and mechanical properties of starch-cellulose acetate/silver sulfadiazine matrices prepared by melt extrusion

Starch-cellulose acetate matrices containing silver sulfadiazine were produced using melt extrusion for application in drug delivery devices (DDDs). The influence of the extrusion parameters (screw speed and temperature) on the morphological and mechanical properties of the matrices was evaluated at three different levels. The microstructural characterization of all matrices showed that an increase in the screw speed enhances the porosity and drug dispersion, while an increase in the extrusion temperature decreases the pore diameter of the matrices. Mechanical results did not show significant differences between the elastic modulus values for the matrices; however, a faster screw speed led to higher ultimate strength and strain at failure values. Results obtained in the dynamic mechanical analysis showed that the glass transition and loss tangent (tan δ) peak values became higher with increasing screw speed and temperature.

Starch cellulose acetate co-acrylate (SCAA) polymer as a drug carrier

The present study aims to create a controlled-release system through the preparation and characterization of starch cellulose acetate co-acrylate (SCAA) polymer for application as a carrier for cancer drugs. SCA was prepared from maize starch and different ratios of cellulose acetate. The obtained product SCA was reacted with acrylic acid monomer to give cellulose acetate co-acrylate. The best ratio of starch to cellulose acetate was found to be 90:10, giving a stable product with acrylic acid. The cancer drug 8-(2-methoxyphenyl)-3,4-dioxo-6-thioxo-3,4,6,7-tetrahydro-2h-pyrimido[6,1-c]-[1,2,4]triazine-9-carbonitrile was dissolved in dimethylformamide then added gradually at the end of the previous reaction under stirring for 15 min. The prepared polymers with and without the drug were characterized by Fourier-transform infrared spectroscopy. Cuboids discs of the prepared polymer/drug were subjected to drug release in aqueous media at different pH values. The release was measured spectrophotometrically. It was found that the release rate depends on the pH of the aqueous medium as well as on the concentration of the drug loaded onto the polymer carrier. Above pH 12, the polymer containing the drug degraded completely within 1 h after being subjected to alkaline media. Sustained release of drug extended to about 20 days. The amount released depended on the pH of the media in the following order: basic media > acidic media > neutral. According to Higuch’s equation, the diffusion coefficient was found to be 4.2 × 10−8 and 5.5 × 10−8 cm s−1 for the two evaluated concentrations (1.5 and 2 %) of active organic compound (drug).

Microhardness of starch based biomaterials in simulated physiological conditions

In this work the variation of the surface mechanical properties of starch-based biomaterials with immersion time was followed using microhardness measurements. Two blends with very distinct water uptake capabilities, starch/cellulose acetate (SCA) and starch/poly(ε-caprolactone) (SPCL), were immersed in a phosphate buffer solution (PBS) at 37.5 °C for various times. The microhardness of the blends decreased significantly (∼50% for SPCL and ∼94% for SCA), within a time period of 30 days of immersion, reflecting the different hydrophilic character of the synthetic components of the blends. The dependence of microhardness on the applied loading time and load was also analysed and showed a power law dependency for SCA. Water uptake and weight loss measurements were performed for the same immersion times used in the microhardness experiments. The different swelling/degradation behaviour presented by the blends was related to the respective variation in microhardness. Moreover, complementary characterization of the mechanical properties of SCA and SPCL was accomplished by dynamic mechanical analysis (DMA) and creep measurements. Microhardness measurements proved to be a useful technique for characterizing the mechanical behaviour near the surface of polymeric biomaterials, including in simulated physiological conditions.

Preliminary study on the adhesion and proliferation of human osteoblasts on starch-based scaffolds

Up to today, several techniques have been used to produce biodegradable porous scaffolds for tissue engineering. In this work, a new technique based on extrusion by using blowing agents in combination with a 50:50 (wt.%) blend of starch/cellulose acetate (SCA) was studied. The results show that by using this technique it was possible to obtain scaffolds with 70% of porosity and a fully interconnected network of pores, with sizes ranging from 200 to 500 μm. After their production, the mechanical properties of these scaffolds were tested, presenting a compressive modulus of 124.6±27.2 MPa and a compressive strength of 8.0±0.9 MPa. These values are within the best found in the literature and show that by using this technique, it is possible to produce scaffolds that, from a mechanical standpoint, may be suitable for bone tissue engineering. Cell culturing experiments showed that cells were viable and that there were no signs of cellular death after 3 weeks of culture. Finally, biochemical assays demonstrate that cells maintained the osteogenic phenotype throughout the experiment and deposition of mineralized extracellular matrix could be detected.

The biocompatibility of novel starch-based polymers and composites: in vitro studies

Studies with biodegradable starch-based polymers have recently demonstrated that these materials have a range of properties, which make them suitable for use in several biomedical applications, ranging from bone plates and screws to drug delivery carriers and tissue engineering scaffolds. The aim of this study was to screen the cytotoxicity and evaluate starch-based polymers and composites as potential biomaterials. The biocompatibility of two different blends of corn-starch, starch/ethylene vinyl alcohol (SEVA-C) and starch/cellulose acetate (SCA) and their respective composites with hydroxyapatite (HA) was assessed by cytotoxicity and cell adhesion tests. The MTT assay was performed with the extracts of the materials in order to evaluate the short-term effect of the degradation products. The cell morphology of L929 mouse fibroblast cell line was also analysed after direct contact with polymers and composites for different time periods and the number of cells adhered to the surface of the polymers was determined by quantification of the cytosolic lactate dehydrogenase (LDH) activity. Both types of starch-based polymers exhibit a cytocompatibility that might allow for their use as biomaterials. SEVA-C blends were found to be the less cytotoxic for the tested cell line, although cells adhere better to SCA surface. The cytotoxicity test also revealed that SCA and SEVA-C composites have a similar response to the one obtained for SCA polymer. Scanning electron microscopy (SEM) analysis showed that cells were much more spread on the SCA polymer and LDH measurements showed a higher number of cells on this surface.

THERMAL CHARACTERIZATIONS OF WOOD FLOUR/STARCH CELLULOSE ACETATE COMPOUNDS

Thermogravity analysis (TGA) and differential scanning calorimetric (DSC) analysis, as well as dynamic thermal analysis (DMA), were carried out to study the interfacial interaction between wood flour (WF) and starch/cellulose acetate (SCA) blend. It was found that the main components in the compounds, namely, starch, cellulose, and cellulose acetate, started to decompose at around 330°C, a characteristic temperature for breaking glycoside-linked glucose units. Complexation of lignin in WF with amylose in SCA occurred during compounding, which gave rise to new crystallites that have a melting point of around 160°C. Hydrogen bonding is believed to play a key role in the crystallization. With increasing WF content, both the glass transition temperature and softening temperature increase as a result of the restricted molecular chain mobility imposed by rigid cellulose filaments. In addition, the DMA data revealed that amylose can occur as linkages in the crystallites. All these observations indicated that the interfacial adhesion between SCA and WF is relatively strong, even in absence of a coupling agent.

Preparation, processing and characterization of biodegradable wood flour/starch-cellulose acetate compounds

A novel biodegradable material was prepared by compounding, in different proportions, pine wood flour (WF) and a commercial starch-cellulose acetate blend on a configurable co-rotating twin screw extruder. After pelletizing, the compounds were injection moulded and the mechanical and rheological properties of the mouldings determined. As the content of wood flour increases up to 50% (wt/wt), the tensile strength and the modulus improve significantly, whereas the toughness drops gradually. The effect of the wood flour content on the shear viscosity is complex, being impossible to establish a linear relationship between the two. The shear viscosity decreases with shear rate, but for a level of 40% and 50% of WF there is evidence of a quasi-Newtonian behaviour, irrespective of the test temperature. Compounds with 50% WF present the highest tensile strength and modulus but are difficult to process. However, the processability can be improved by using glycerol as plasticizer, without paying a too severe penalty in mechanical properties. In fact, by adding 15% glycerol (wt/wt), compounds with 50% WF can be successfully injection moulded into specimens with good mechanical properties.