Biobased Content Research Articles

A statistical approach to develop biocomposites from epoxy resin, poly(furfuryl alcohol), poly(propylene carbonate), and biochar

ABSTRACTEpoxy composites are typically petroleum based and prone to fracture. Increasing concerns about climate change have motivated scientists to find green alternatives. To address both drawbacks, effect of addition of poly(propylene carbonate) polyol (PPC), a polyol derived from carbon dioxide, and biochar, a byproduct of pyrolysis in an epoxy/poly(furfuryl alcohol) (PFA) network was studied. It is hypothesized that addition of PPC will increase impact strength while addition of inexpensive biochar will offset cost of final product. In addition, incorporation of PFA, PPC, and biochar can increase biobased content of thermoset. A statistical approach was used to find a systematic correlation between constituent contents and mechanical properties of biocomposites. Mixture design of experiment and backward elimination regression were used to model mechanical properties of biocomposites. The fitted models showed a great ability to predict mechanical properties of new formulations. Addition of 10% biochar increased tensile strength and toughness by 13% and 34%, respectively. Biochar also increased modulus while it had adverse effect on impact strength. Promising effect of PPC on toughening of matrix was proved and it was found that addition of 30% of PPC increased impact strength by fivefolds. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45307.

Determining the bio-based content of bio-plastics used in Thailand by radiocarbon analysis

Presently, there is an increased interest in the development of bio-plastic products from agricultural materials which are biodegradable in order to reduce the problem of waste disposal. Since the amount of modern carbon in bio-plastics can indicate how much the amount of agricultural materials are contained in the bio-plastic products, this research aims to determine the modern carbon in bio-plastic using the carbon dioxide absorption method. The radioactivity of carbon-14 contained in the sample is measured by liquid scintillation counter (Tri-carb 3110 TR, PerkinElmer). The percentages of bio-based content in the samples were determined by comparing the observed modern carbon content with the values contained in agricultural raw materials. The experimental results show that only poly(lactic acid) samples have the modern carbon content of 97.4%, which is close to the agricultural materials while other bio-plastics types are found to have less than 50% of the modern carbon content. In other words, most of these bio-plastic samples were mixed with other materials which are not agriculturally originated.

Business Roundup

Business Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2017, 95 (21), p 15May 22, 2017Cite this:C&EN 95, 21, 15AbstractReichhold and Polynt got the go-ahead for their merger from the European Commission, provided Reichhold divests its Étain, France, unsaturated polyester resins plant to a buyer approved by the commission. In April, Reichhold penned a deal to sell the Étain plant to Ashland. Covestro will expand by 50% to 600,000 metric tons per year the capacity of its recently-expanded polycarbonate plant in Shanghai. The company will raise capacity not by building new production lines but by upgrading equipment on the units that are currently operating. Cargill has acquired BioBased Technologies, a maker of vegetable-based polyols based in Rogers, Ark. The business’s production method will bring to Cargill flexible foam products with high biobased content. Vivet Therapeutics, a Paris-based biotech start-up, has raised $41.7 million in funding to develop gene therapies for rare, inherited metabolic diseases. Investors include HealthCap, Novartis Venture Fund, and Roche Venture Fund. Ashland has completed itsView: PDF | Full Text HTML

Design, characterization and in vitro evaluation of novel amphiphilic block sunflower oil-based polyol nanocarrier as a potential delivery system: Raloxifene-hydrochloride as a model

Presently, modern pharmaceuticals, are almost exclusively derived from the arduous refining of petroleum whose supply is inherently unsustainable. In order to address this issue bio-based materials are increasingly being used for chemical synthesis, particularly in drug delivery systems. Biodegradable and biocompatible hyper-branched polyol (an alcohol containing three or more hydroxyl groups) was synthesized via a facile method through the ring-opening and thiol-ene click reactions at room temperature. Due to the bio-based content of the polyol backbone, the synthesized polyol had both excellent biodegradability and low cytotoxicity. Raloxifene hydrochloride, an oral selective estrogen receptor modulator, was used as a hydrophobic drug model to test the potential of polyol as a drug delivery system carrier. Polyol showed an amphiphilic character and could be prepared as a nanoparticle for the sustained delivery of raloxifene hydrochloride, a drug with poor bioavailability in aqueous solution. Raloxifene hydrochloride was readily encapsulated in the lipophilic core of polyol whose branched hydroxyls were on the external part of the prepared nanoparticles. The diameter of the nanoparticles was 94±0.43nm, their drug entrapment efficiency was 93±0.5% and they showed a sustained release profile (17±1.5% after 4weeks). The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay showed low toxicity towards human osteoblast MG-63 cells. Based on its good biodegradability and low cytotoxicity, polyol provides a bio-based source for the design new drug delivery systems.

All Biomass and UV Protective Composite Composed of Compatibilized Lignin and Poly (Lactic-acid)

Utilization of carbon-neutral biomass became increasingly important due to a desperate need for carbon reduction in the issue of global warming in light of replacing petroleum-based materials. We used lignin, which was an abundant, low cost, and non-food based biomass, for the development of all biomass-based films and composites through reactive compatibilization with poly (lactic-acid) (PLA). Using a facile and practical route, the hydrophilic hydroxyl groups of lignin were acetylated to impose the compatibility with PLA. The solubility parameter of the pristine lignin at 26.3 (J/cm3)0.5 was altered to 20.9 (J/cm3)0.5 by acetylation allowing the good compatibility with PLA at 20.2 (J/cm3)0.5. The improved compatibility of lignin and PLA provided substantially decreased lignin domain size in composites (12.7 μm), which subsequently gave transparent and UV-protection films (visual transmittance at 76% and UV protection factor over 40). The tensile strength and elongation of the developed composite films were increased by 22% and 76%, respectively, and the biobased carbon content was confirmed as 96 ± 3%. The developed PLA/lignin composites provided 100% all-biomass contents and balanced optical and mechanical properties that could broaden its eco-friendly applications in various industries.

Synthesis of bio-based polyurethane coatings from vegetable oil and dicarboxylic acids

Bio-based thermoset polyurethane (PU) coatings comprised of polyesteramides were prepared from Gossypium arboreum (cotton seed) plant oil as a renewable source. Oil was first converted into fatty amide that was transformed into a series of polyesteramide polyols upon esterification with different dicarboxylic acids and anhydride. In the preparation of polyesteramide polyols, to increase bio-based content five different dicarboxylic acids of renewable nature were used to replace petroleum counterparts. Structures of polyols were confirmed using NMR and FT-IR spectroscopic techniques. Molecular weights of polyols were determined using gel permeation chromatography. Bio-based polyesteramide polyols were used to prepare thermoset PU by treating with aromatic diisocyanate. The thermal behavior of all prepared polyurethane coatings was determined using a thermogravimetric analyzer and differential scanning calorimeter. Coatings prepared using renewable source based polyesteramides were with high suitable curing, mechanical/chemical performances, alkali/acid resistance, and hydrophobicity. Compared to conventional PU coatings, the prepared coatings possess the superior properties such as gloss, adhesion, and pencil hardness. Thus present work demonstrates Gossypium arboreum plant oil and dicarboxylic acids as newer eco-friendly raw materials for PU coatings and compared with standard petro based polyols.

BASF promotes biomass approach

Falk Bouwsystemen, a Dutch maker of polyurethane-based insulating panels, is working with BASF to get renewable resources into its products. Under the scheme, BASF is adding renewable resources such as biogas or biobased liquids to its basic chemical feedstock stream. Polyurethane ingredients made with these chemicals are assigned a virtual “bio share” in a range from 25 to 100%. This share is credited to customers that want biobased content. BASF says the approach promotes sustainable production without changing product quality or properties.

A preliminary evaluation of bio-based epoxy resin hardeners for maritime application

A screening of different hardeners derived from cashew nut shell liquid (CNSL) was performed; they were compared to a conventional hardener in an epoxy resin system for composite production by infusion process. All samples were submitted to different post-curing processes before tensile strength and moisture uptake were evaluated. It was observed that the use of CNSL hardeners produced cured epoxies similar in Young’s Modulus (YM) to the conventional hardener with a lower moisture uptake however, the hardeners resulting in a low YM had a marked reduction in moisture uptake. Studies of the post-curing process showed that the moisture uptake of the conventional system can be improved but, depending on the temperature applied, the process can be detrimental to the CNSL hardeners, provided that moisture uptake was increased after post-curing. The results indicate that biobased content can be introduced to a conventional epoxy resin system by replacing the conventional hardener commonly used by a sustainable one derived from cashew nut shell liquid with an additional moisture uptake reduction.

Soft polyurethane elastomers with adhesion properties based on palm olein and palm oil fatty acid methyl ester polyols

Soft polyurethane (PU) elastomers with >70% bio-based content and with properties characteristic of pressure sensitive adhesives were prepared from an equimolar ratio of a polyol derived from palm oil fatty acid methyl ester (PolyFAME-EG polyol) and palm olein polyols (Pioneer E-135 and Pioneer M-60) cured with 2,4′- and 4,4′- diphenylmethane diisocyanate isomeric mixture at isocyanate to hydroxyl equivalent weight ratio (Isocyanate Index) of 1.02 and 0.73. FTIR analyses of the resulting elastomers indicate high levels of free non-hydrogen bonded urethanes, indicating phase mixing of hard and soft segments, which explains the transparent nature of the elastomers. The physical properties of the elastomers were correlated with the cross-link density of the palm olein polyols and Isocyanate Index. Elastomers produced at an Isocyanate Index of 1.02 ranges in hardness from 21 to 67 Shore A which correlated with the average polyol functionality. However, at an Isocyanate Index of 0.72 the resulting elastomers were very soft with hardness ranging from 1 to 4 Shore A and with T-peel adhesion to polypropylene in the range from 2.27 to 1.98N/25mm. Based on these results, a polyurethane matrix with a high renewable content of palm oil polyols can be used as a platform for the development of transparent elastomers that can be used as soft energy-absorbing materials with potential use in pressure sensitive adhesives.

Development and weatherability of bio-based composites of structural quality using flax fiber and epoxidized sucrose soyate

Composites having high bio-based content with properties and costs rivaling those consisting of synthetic constituents are a goal of much current research. The obvious material choices — vegetable oil based resins and natural fibers — present the challenges of poor resin properties and weak fiber/matrix bonding, respectively. Conventional methods of overcoming poor resin quality involve the incorporation of additives, which dilute the resulting composite's bio-content and increases cost. To overcome these limitations while maintaining high bio-content, in this study, a newly developed biobased resin, epoxidized sucrose soyate (ESS), is combined with surface-treated flax fiber to produce novel bio-composites. Properties of manufactured composites were compared against those using epoxy resin reinforced with flax fiber. In addition to mechanical property evaluation, accelerated weathering was performed on the manufactured composites to evaluate the mechanical properties after exposing to UV and moisture. The results of this study revealed the successful production of bio-composites having properties that meet or exceed those of conventional pultruded members while having 85% bio-content. Moreover, composites using treated flax fiber and ESS resin showed less degradation in properties and appearance after accelerated weathering exposure.

New bio-based polymeric thermosets synthesized by ring-opening polymerization of epoxidized soybean oil with a green curing agent

New polymeric thermosets with a high bio-based content were obtained by the ring-opening polymerization of two biomass derivatives, epoxidized soybean oil and maleopimaric acid, catalysed by 2-ethyl-4-methylimidazole. Maleopimaric acid with a rigid hydrogenated phenanthrene ring structure was successfully synthesized in a large quantity from abietic acid and maleic anhydride using p-toluene sulfonic acid as a catalyst, by adapting and optimizing an industrial strategy. The advantages of using maleopimaric acid as a curing agent for epoxidized soybean oil, compared with its petroleum-based analogues, were studied in detail. The results showed that the total heat release for the ring-opening polymerization of epoxidized soybean oil and maleopimaric acid was only 31.7kJ/mol epoxy group. The tensile properties and glass transition temperature of the thermosets cured by maleopimaric acid were close to those of the products cured by the analogue with a cycloaliphatic ring, while the breaking elongation and storage modulus at room temperature of the former were greatly larger, exhibiting values of 61.5% and 1268MPa, respectively. Additionally, the products cured with maleopimaric acid had the best thermal stability with a 10%-weight-loss temperature up to 349°C and satisfactory chemical and water resistance.

Curing kinetics of bio‐based epoxy resin based on epoxidized soybean oil and green curing agent

New thermoset with a high bio‐based content was synthesized by curing epoxidized soybean oil (ESO) with a green curing agent maleopimaric acid catalyzed by 2‐ethly‐4‐methylimidazole. Non‐isothermal differential scanning calorimetry and a relatively new integral isoconversional method were used to analyze the curing kinetic behaviors and determine the activation energy (Ea). The two‐parameter Šesták–Berggren autocatalytic model was applied in the mathematical modeling to obtain the reaction orders and the pro‐exponential factor. For anhydride/epoxy group molar ratio equal to 0.7, Ea decreased from 82.70 to 80.17 kJ/mol when increasing the amount of catalyst from 0.5 to 1.5 phr toward ESO. The reaction orders m and n were 0.4148 and 1.109, respectively. The predicted non‐isothermal curing rates of Šesták–Berggren model matched perfectly with the experimental data. © 2016 American Institute of Chemical Engineers AIChE J, 63: 147–153, 2017

A study of mechanical properties of biobased epoxy network: Effect of addition of epoxidized soybean oil and poly(furfuryl alcohol)

ABSTRACTA novel biobased thermoset interpenetrating network was introduced in this study. Epoxidized soybean oil (ESO) and poly(furfuryl alcohol) (PFA) were added to a commercial biobased epoxy resin. It was hypothesized that addition of ESO and PFA can decrease brittleness of bioepoxy resin and also increase biobased content. Mechanical properties of samples were evaluated using tensile and impact test. It was found that the addition of ESO and PFA increased notched Izod impact energy by 76.6%. This significant increase was related to incorporation of long flexible chains of ESO into the matrix. Hybridization of ESO and PFA in bioepoxy reduced tensile strength (around 70%), tensile modulus (around 90%), and glass transition temperature in comparison to neat bioepoxy. Tensile strength and modulus of hybridized system can be further improved by addition of natural fibers and the resultant composite may be considered as a good candidate for applications in which damping properties are important. Crosslink density was calculated using dynamic mechanical analysis and a decrease in crosslink density was observed in hybridized system. PFA domains were observed in the matrix using atomic force microscopy in peak force quantitative nano‐mechanical mode and it revealed inhomogeneity in the crosslinked structure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44352.

Synthesis, characterization and curing optimization of a biobased thermosetting resin from xylitol and lactic acid

A biobased thermoset resin was synthesized by direct condensation reaction of lactic acid with xylitol followed by the end-functionalization of the hydroxyl groups of branches by methacrylic anhydride. Chemical structures of resins were evaluated and confirmed by 13C NMR and Fourier-transform infrared spectroscopy (FT-IR). Different techniques were employed for the optimization of the curing process. Techniques including Microscopy, Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Thermal Analysis (DMTA) were employed for characterization of the cured resins. Thermogravimetric analyses (TGA) were also carried out to check the thermal stability of the cured resins. The viscosity of the neat resin was measured at different temperatures and different stress levels. Water adsorption tests were also carried out to check the water absorption properties of cured resins. The glass temperature (Tg) of the resin was 98°C, and the viscosity of the resin was 2.97Pas at room temperature which drops to 0.07Pas upon increasing the temperature to 85°C. The biobased content of the resin was calculated as 77%. Cheap raw materials, high biobased content, biodegradability, good thermomechanical and rheological properties, good processability and good thermal stability are of advantages of the synthesized resin which makes the resin comparable with commercial unsaturated polyester resins.

Exploring the climate impact effects of increased use of bio-based materials in buildings

Whenever Life Cycle Assessment (LCA) is used to assess the climate impact of buildings, those with high content of biobased materials result with the lowest impact. Traditional approaches to LCA fail to capture aspects such as biogenic carbon exchanges, their timing and the effects from carbon storage. This paper explores a prospective increase of biobased materials in Swedish buildings, using traditional and dynamic LCA to assess the climate impact effects of this increase. Three alternative designs are analysed; one without biobased material content, a CLT building and an alternative timber design with “increased bio”. Different scenario setups explore the sensitivity to key assumptions such as the building’s service life, end-of-life scenario, setting of forest sequestration before (growth) or after (regrowth) harvesting and time horizon of the dynamic LCA. Results show that increasing the biobased material content in a building reduces its climate impact when biogenic sequestration and emissions are accounted for using traditional or dynamic LCA in all the scenarios explored. The extent of these reductions is significantly sensitive to the end-of-life scenario assumed, the timing of the forest growth or regrowth and the time horizon of the integrated global warming impact in a dynamic LCA. A time horizon longer than one hundred years is necessary if biogenic flows from forest carbon sequestration and the building’s life cycle are accounted for. Further climate impact reductions can be obtained by keeping the biogenic carbon dioxide stored after end-of-life or by extending the building’s service life, but the time horizon and impact allocation among different life cycles must be properly addressed.

Replacing fossil based plastic performance products by bio-based plastic products—Technical feasibility

Larger scale market introduction of new bio-based products requires a clear advantage regarding sustainability, as well as an adequate techno-economic positioning relative to fossil based products. In a previous paper [Broeren et al., 2016], LCA results per kg and per functionality equivalent of bio-based plastics were presented, together with economic considerations. The present paper discusses the mechanical and thermal properties of a range of commercially available bio-based plastics based on polylactic acid (PLA), cellulose esters, starch and polyamides, and the feasibility of replacing fossil-based counterparts based on performance. The evaluation is approached from an end user perspective. First, potentially suitable bio-based plastics are selected based on manufacturers’ specifications in technical data sheets, then a first experimental evaluation is performed on injection moulded ISO specimens, and finally a further selection of plastics is tested on large 50×70cm panels. This technical feasibility study indicates that so far bio-based plastics do not completely match the properties of high performance materials like flame retardant V-0 PC/ABS blends used in electronic devices. The performance gap is being decreased by the development of stereocomplex PLA and hybrid PLA blends with polycarbonate, which offer clearly improved properties with respect to maximum usage temperature and toughness. In addition, several materials meet the V-0 flammability requirements needed in specific durable applications. On the other hand, improving these properties so far has negative consequences for the bio-based content. This study also shows that replacement of bulk polymers like PS is feasible using PLA compounds with a bio-based content as high as 85%.

Synthesis and characterization of advanced biobased thermoplastic nonisocyanate polyurethanes, with controlled aromatic-aliphatic architectures

The aim of this study was the elaboration of thermoplastic and biobased nonisocyanate polyurethanes (TNIPUs) based on different aromatic-aliphatic architectures. A rigid aromatic bis(cyclic carbonate) was synthesized from terephthalic acid, and subsequently used with various diamines for the preparation of TNIPUs. A two-step method was investigated to design advanced macromolecular architectures. All TNIPUs and corresponding intermediates were fully characterized. The influence of various parameters such as the ratio between the constituting building blocks and the chemical structure on NIPU properties was studied. Thermal and mechanical results show that the TNIPUs presenting the highest molar masses and the highest properties were synthesized from dimer diamine prepolymers. A high content of terephthalic acid and short-chain diamine increases the glass transition temperature and leads to good performances, with a balance between elongation and tensile strength properties. The final TNIPUs present biobased content up to 76%.

Synthesis and characterization of castor oil-segmented thermoplastic polyurethane with controlled mechanical properties

Novel castor oil-segmented thermoplastic polyurethane series (PUs) have been prepared and extensively characterized in this study. The castor oil, poly(tetrahydrofuran) polyol, and poly(dimethylsiloxane) have been employed as soft segments in the polymer synthesis with a maximum bio-based content up to 14.1wt%. We demonstrate here that it is possible to prepare thermoplastic polyurethane containing castor oil via polyaddition approach in which the formation of prepolymer needs to be carried out with the addition of reasonably small amount of castor oil together with excess amount of the diisocyanate in the very first step. This is followed by the addition of the other polyols and finally a low molecular weight chain extender. The developed synthesis resulted in the formation of branched thermoplastic polyurethane with an elongation at break of about 1200%, which is considerably high compared to reported values for polyurethanes containing castor oil as soft segments. We have demonstrated that mechanical properties and flexibility of polyurethane can be significantly altered by both incorporated castor oil and controllable poly(dimethylsiloxane)/poly(tetrahydrofuran) polyol ratio during the synthesis. Especially the synthesized polyurethanes exhibited good biocompatibility and high transparency, which are useful properties for polymers as potential biomaterials. In addition, thermal stability and thermal transition of polyurethanes have been investigated.

Sustainable biobased blends from the reactive extrusion of polylactide and acrylonitrile butadiene styrene

ABSTRACTPolymer blends containing poly(lactic acid) (PLA) and acrylonitrile butadiene styrene (ABS) with high biobased content (50%) were made by extrusion and injection molding. Two additives, one acrylic copolymer and one chain extender were used separately and in combination to increase mechanical properties. Interestingly, the combination of both the acrylic copolymer and chain extender worked to synergistically increase the impact strength by almost 600%. This was attributed to the complementary additive toughening effects which allowed increased energy dissipation of the blend at high speed testing, such as in the impact test. Morphology and rheology investigation showed that the two additives worked together to vastly change the dispersion and phase sizes, suggesting a decreased tension between the PLA and ABS. Finally, Fourier transform infrared spectroscopy supported the evidence that the epoxy groups of the chain extender undergo ring opening to react with the functional groups of the PLA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43771.

Perspective on Polylactic Acid (PLA) based Sustainable Materials for Durable Applications: Focus on Toughness and Heat Resistance

Evolution of the bioplastics industry has changed directions dramatically since the early 1990s. The latest generation is moving toward durable bioplastics having high biobased content. The main objective is to replace “fossil carbon” with “renewable carbon”, a holistic strategy to mitigate climate change by minimizing the environmental impact of a product throughout its life cycle. Durable bioplastics is desired for multiuse long-term application in automotive, electronics and other industries. One necessary requirement for them is to be both tough and strong, yet the two attributes are often mutually exclusive. Does this mean a biobased and biodegradable polymer as polylactic acid (PLA) with its high strength but low toughness cannot be adopted for durable applications? Well, not exactly; this is where the concept of tailoring the properties of PLA to achieve stiffness–toughness balance along with acceptable heat resistance comes into play. In this perspective, we summarize the recent research progress ...