Renewably sourced phenolic resins from lignin bio‐oil

Traditional lignin pyrolysis generates a bio‐oil with a complex mixture of alkyl‐functionalized guaiacol and syringol monomers that have limited utility to completely replace phenol in resins. In this work, formate assisted fast pyrolysis (FAsP) of lignin yielded a bio‐oil consisting of alkylated phenol compounds, due to deoxyhydrogenation, that was used to synthesize phenol/formaldehyde resins. A solvent extraction method was developed to concentrate the phenolics in the extract to yield a phenol rich monomer mixture. Phenolic resins were synthesized using phenol (phenol resin), FAsP bio‐oil (oil resin), and an extract mimic (mimic resin) that was prepared to resemble the extract after further purification. All three phenolic sources could synthesize novolac resins with reactive sites remaining for subsequent resin curing. Differential scanning calorimetry and thermogravimetric analysis of the three resins revealed similar thermal and decomposition behavior of phenol and the mimic resins, while the oil resin was less stable. Resins were cured with hexamethylenetetramine and the mimic resin demonstrated improved curing energies compared to the oil resin. The adhesive strength of the mimic resin was found to be superior to that of the oil resins. These results confirmed that extracting a mixture of substituted aromatics from FAsP bio‐oil could synthesize resins with properties similar to those from phenol and improved over the parent bio‐oil. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44827.     

High performance bio‐based thermosetting resins composed of tung oil and bismaleimide

The reaction of tung oil (TO) and 1,1′‐(methylenedi‐4,1‐phenylene)bismaleimide (BMI) in 1,3‐dimethyl‐2‐imidazolidinone (DMI) at 150°C for 4 h and subsequent precipitation gave TO/BMI prepolymer, which was cured at 200°C for 2 h gave crosslinked TO/BMI product with CC ratio from 1/1 to 1/4. The FE‐SEM analysis revealed that all the cured products are homogeneous and no phase separation was observed. The glass transition temperature and 5% weight loss temperature of the cured TO/BMI increased with increasing BMI content. The maximal tensile strength (38.1 MPa) and modulus (2.6 GPa) were obtained for the cured products with the CC ratios of 1/2 and 1/3, respectively. To evaluate the reaction of TO and BMI, the model reaction products of TO and N‐phenylmaleimide (PMI) in DMI were analyzed by ¹H‐NMR spectroscopy. The NMR data of the reaction products of TO/PMI with the CC ratio 2/1, 1/1, 1/2, 1/3, and 1/4 at 150°C for 24 h revealed that Diels‐Alder reaction preferentially occurred at 2/1, and that ene reaction and other reactions such as radical homo and copolymerization gradually increased with decreasing CC ratio of TO/PMI. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

High‐performance bio‐based thermosetting resins composed of dehydrated castor oil and bismaleimide

The reaction of dehydrated castor oil (DCO) and 1,1′‐(methylenedi‐4,1‐phenylene)bismaleimide (BMI) in 1,3‐dimethyl‐2‐imidazolidinone (DMI) at 130°C for 6 h and subsequent precipitation gave DCO/BMI prepolymer, which was cured at 200°C for 2 h gave DCO/BMI cured product. The FE‐SEM analysis revealed that the cured products with C?C ratio 2/1 and 1/1 are homogeneous, whereas phase separation occurs for the 1/2 product. The glass transition temperature, 5% weight loss temperature, and tensile modulus of the cured DCO/BMI increased with increasing BMI content. Regarding the tensile strength, the cured DCO/BMI 1/1 product showed the highest value. To evaluate the reaction of DCO and BMI, the model reaction products of DCO and N‐phenylmaleimide (PMI) in DMI were analyzed by ¹H NMR spectroscopy. The ¹H NMR data of DCO revealed that DCO has about 4.8 CH?CH bonds per triglyceride and that the ratio of conjugated and nonconjugated diene moieties is about 41/59. The NMR data of the reaction products of DCO/PMI with the C?C ratio 2/1 and 1/1 at 200°C for 24 h revealed that both Diels–Alder and ene reactions occurs in addition to radical polymerization. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Research progress on bio‐based thermosetting resins

Compared with the rapid progress on bio‐based thermoplastics, research on bio‐based thermosetting resins should have attracted much more attention, considering that they will have a bright future. In this paper, the current research progress on bio‐based thermosetting resins is reviewed. We pay special attention to the synthesis and investigation of properties of epoxies and unsaturated polyesters derived from renewable plant oil, cardanol, rosin acid, lignin, glycerol, gallic acid, furan, isosorbide, itaconic acid, etc. This mini review gives an overall perspective for bio‐based thermosets.© 2015 Society of Chemical Industry     

Fast pyrolysis bio‐oil as precursor of thermosetting epoxy resins

Fast pyrolysis bio‐oil was employed as a source of phenolic compounds in the production of a bio‐based polymeric network. The bio‐oil was reacted with epichlorohydrin in alkaline medium using benzyltriethylammonium chloride as a phase transfer catalyst. The amount of free phenolic hydroxyl groups before and after modification was quantified through ³¹P‐NMR spectroscopy; and the epoxy content of the bio‐oil upon the chemical functionalization was measured by means of a titration using HBr in acetic acid solution. Grafting of epoxy functions onto the monomer`s structure was studied by FTIR. Likewise, α‐resorcylic acid was also modified with reactive epoxy moieties, and used as low molecular weight comonomer. The epoxidized derivatives of the bio‐oil were cured in epoxy polymers with 4‐dimethylaminopyridine. Thermo‐mechanical characterization showed that the obtained materials behave as thermoset amorphous polymers, exhibiting modulus values ranging from approximately 1.5–3.4 GPa at room temperature and glass transition temperatures above 100°C. POLYM. ENG. SCI., 58:1296–1307, 2018. © 2017 Society of Plastics Engineers     

Vegetable oil based polyurethanamide/organo‐montmorillonite bio‐nanocomposite

The present work describes the synthesis and characterization of polyurethanamide/organo‐montmorillonite bio‐nanocomposites (OBNC) from Linseed oil‐a renewable resource. The aim of the work is (i) to widen the scope of application and improve the performance of vegetable oil based polymers, and (ii) to investigate the effect of introduction of modified clay on their structure, morphology, thermal stability, and coating properties. OBNC has been prepared by in situ polymerization of Linseed oil derived diol fattyamide and tolulylene‐2,4‐diisocyanate in the presence of different contents of OMMT (0.5–2.5 mass % in minimum amount of dimethylformamide) at room temperature. OBNC has been characterized by optical microscopy, FTIR, XRD, TEM, and TGA, which confirm the formation of OBNC. OBNC produced tough, scratch‐resistant, impact resistant, flexibility retentive coatings, which cure at room temperature with improved coating performance and thermal stability than virgin polymer. Amongst all the compositions, OMMT‐1.5 showed the best coating properties, with good scratch hardness (3.5 kg), impact (passes 200 lb/inch.) and bent test values (passes 1/8 inch). It can be commercially used as effective green coating material in future. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40278.     

Epoxidized vegetable oil and bio‐based materials as PVC plasticizer

Phthalate esters received a considerable attention owing to its various applications and the harmful health effects resulting from phthalate exposure; thus, finding an alternative to phthalate derivatives became a necessity. Phthalate esters are commonly used as plasticizer in polymer formulation; in particular for poly(vinyl chloride) (PVC) formulation. According to the researches in the last 18 years, epoxidized vegetable oils are one of the alternatives that are strongly encouraged to substitute phthalate esters since they were proven to be valid in various applications, eco‐friendly and sustainable resource. However, most of the production practices for epoxidized vegetable oil are via conventional epoxidation that concentrates on a catalyst that is homogeneous and non‐reusable. This type of catalyst, however, causes several problems later in the process. Therefore, the selective epoxidation of vegetable oils process requires new catalytic systems that are more aligned with the green chemistry principles. This article reviews the harmful health effects associated with the exposure to phthalate esters products, explains the usage of oleochemicals resources as a substitute to phthalate esters and describes different approaches for the epoxidation of vegetable oils. Finally, it draws attention to the usage of epoxy and bio‐based compounds as plasticizers in PVC manufacturing. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46270.     

Synthesis and characterization of bio‐based thermosetting resins from lactic acid and glycerol

A bio‐based thermoset resin has been synthesized from glycerol reacted with lactic acid oligomers of three different chain lengths (n): 3, 7, and 10. Lactic acid was first reacted with glycerol by direct condensation and the resulting branched molecule was then end‐functionalized with methacrylic anhydride. The resins were characterized by Fourier‐transform infrared spectroscopy (FT‐IR), by ¹³C‐NMR spectroscopy to confirm the chemical structure of the resin, and by differential scanning calorimetry and dynamic mechanical thermal analysis (DMTA) to obtain the thermal properties. The resin flow viscosities were also measured using a rheometer with different stress levels for each temperature used, as this is an important characteristic of resins that are intended to be used as a matrix in composite applications. The resin with a chain length of three had better mechanical, thermal, and rheological properties than the resins with chain lengths of seven and 10. Also, its bio‐based content of 78% and glass transition temperature of 97°C makes this resin comparable to commercial unsaturated polyester resins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40488.     

Synthesis of bio‐based polyurethanes from epoxidized soybean oil and isopropanolamine

Epoxidized soybean oil (ESO) and isopropanolamine were used to synthesize a new polyol mixture for preparation of bio‐based polyurethanes. The chemical synthetic route for reaction of ESO with isopropanolamine was analyzed by ¹H‐NMR. The results suggested that both ester groups and epoxy groups in ESO had reacted with amino group of isopropanolamine through simultaneous ring‐opening and amidation reactions. Epoxy groups in various situations exhibited different reactivity, and the unreacted epoxy groups were further opened by hydrochloric acid. The synthesized polyol mixture had high hydroxyl number of 317.0 mg KOH/g. A series of polyurethanes were prepared by curing the synthesized polyol mixture with 1,6‐diisocyanatohexance along with different amount of 1,3‐propanediol (PDO) as chain extender. Tensile tests showed that yield strengths of the polyurethanes ranged from 2.74 to 27.76 MPa depending on the content of PDO. Differential scanning calorimetry analysis displayed one glass transition temperature in the range of 24.4–28.7°C for all of the polyurethane samples, and one melt peak at high content of PDO. Thermogravimetric analysis showed that thermal degradations of the polyurethanes started at 240–255°C. In consideration of simple preparation process and renewable property of ESO, the bio‐based polyurethane would have wide range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis of bio‐based polymeric nanocomposites from acrylated epoxidized soybean oil and montmorillonite clay in the presence of a bio‐based intercalant

Polymeric nanocomposites were synthesized from functionalized soybean‐oil‐based polymer matrix and montmorillonite (MMT) clay using an in situ free radical polymerization reaction. Acrylated epoxidized soybean oil combined with styrene was used as the monomer. Organophilic MMT (OrgMMT) was obtained using a quaternized derivative of methyl oleate, which was synthesized from olive oil triglyceride, as a renewable intercalant. The resultant nanocomposites were characterized using X‐ray diffraction and atomic force microscopy. The effect of increased nanofiller loading on the thermal and mechanical properties of the nanocomposites was investigated using thermogravimetric analysis and dynamic mechanical analysis. It was found that the desired exfoliated nanocomposite structure was achieved when the OrgMMT loading was 1 and 2 wt%, whereas a partially exfoliated or intercalated nanocomposite was obtained for 3 wt% loading. All the nanocomposites were found to have improved thermal and mechanical properties as compared with virgin acrylated epoxidized soybean‐oil‐based polymer matrix. The nanocomposite containing 2 wt% OrgMMT clay was found to have the highest thermal stability and best dynamic mechanical performance. Copyright © 2010 Society of Chemical Industry     

Modification of novel bio‐based resin‐epoxidized soybean oil by conventional epoxy resin

Conventional epoxy resin (DGEBA), in varying proportion, was used to modify epoxidized soybean oil (ESO) based systems, crosslinked by phthalic anhydride. The properties of DGEBA modified ESO systems were investigated by dynamic mechanical analysis, impact testing, tensile and flexural testing, scanning electron microscopy, and thermogravimetric analysis. Single loss factor tan δ peak was obtained for all of the modified systems. The results show the improvement in mechanical properties from their high crosslinking densities through the introduction of DGEBA with increase in initial degradation temperature, as obtained from thermogravimetric analysis. Results approaches to an ideal composition which gives the optimum property. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Development of a bio‐based composite material from soybean oil and keratin fibers

A novel bio‐based composite material, suitable for electronic as well as automotive and aeronautical applications, was developed from soybean oils and keratin feather fibers (KF). This environmentally friendly, low‐cost composite can be a substitute for petroleum‐based composite materials. Keratin fibers are a hollow, light, and tough material and are compatible with several soybean (S) resins, such as acrylated epoxidized soybean oil (AESO). The new KFS lightweight composites have a density ρ ≈ 1 g/cm³, when the KF volume fraction is 30%. The hollow keratin fibers were not filled by resin infusion and the composite retained a significant volume of air in the hollow structure of the fibers. Due to the retained air, the dielectric constant, k, of the composite material was in the range of 1.7–2.7, depending on the fiber volume fraction, and these values are significantly lower than the conventional silicon dioxide or epoxy, or polymer dielectric insulators. The coefficient of thermal expansion (CTE) of the 30 wt % composite was 67.4 ppm/°C; this value is low enough for electronic application and similar to the value of silicon materials or polyimides used in printed circuit boards. The water absorption of the AESO polymer was 0.5 wt % at equilibrium and the diffusion coefficient in the KFS composites was dependent on the keratin fiber content. The incorporation of keratin fibers in the soy oil polymer enhanced the mechanical properties such as storage modulus, fracture toughness, and flexural properties, ca. 100% increase at 30 vol %. The fracture energy of a single keratin fiber in the composite was determined to be about 3 kJ/m² with a fracture stress of about 100–200 MPa. Considerable improvements in the KFS composite properties should be possible by optimization of the resin structure and fiber selection. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1524–1538, 2005     

Characterisation of the mixture product of ether‐soluble fraction of bio‐oil (ES) and bio‐diesel

A method of upgrading the properties of bio‐oil with bio‐diesel has been taken in this article. Firstly, the unpopular pyrolytic lignin fraction is extracted from bio‐oil using ether, the rest ether‐soluble fraction of bio‐oil, named ES is mixed with bio‐diesel according to emulsification. The optimal conditions for obtaining a stable ES/bio‐diesel mixture are with octanol surfactant dosage of 3% by volume; initial ES to bio‐diesel ratio of 4:6 by volume; stirring intensity of 1200 rpm; mixing time of 15 min and mixing temperature at 30°C. Additionally, selected fuel properties such as viscosity, water content and acid number are measured for characterising the ES/bio‐diesel mixture. Thermogravimetric analysis (TGA) has been used to further evaluate the thermal properties. Data from the TGA and Fourier transform infrared spectroscopy (FTIR) analyses confirm the presence or absence of certain group of chemical compounds in the mixture. Proton and carbon atoms assignments are further confirmed by ¹H NMR (nuclear magnetic resonance) and ¹³C NMR analysis, respectively. © 2011 Canadian Society for Chemical Engineering     

Development of water‐blown bio‐based thermoplastic polyurethane foams using bio‐derived chain extender

Water‐blown bio‐based thermoplastic polyurethane (TPU) formulations were developed to fulfill the requirements of the reactive rotational molding/foaming process. They were prepared using synthetic and bio‐based chain extenders. Foams were prepared by stirring polyether polyol (macrodiol), chain extender (diol), surfactant (silicone oil), chemical blowing agent (distilled water), catalyst, and diisocyanate. The concentration of chain extender, blowing agent, and surfactant were varied and their effects on foaming kinetics, physical, mechanical, and morphological properties of foams were investigated. Density, compressive strength, and modulus of foams decrease with increasing blowing agent concentration and increase with increasing chain extender concentration, but are not significantly affected by changes in surfactant concentration. The foam glass‐transition temperatures increase with increasing blowing agent and chain extender concentrations. The foam cell size slightly increases with increasing blowing agent content and decreases upon surfactant addition (without any dependence on concentration), whereas chain extender concentration has no effect on cell size. Bio‐based 1,3‐propanediol can be used successfully for the preparation TPU foams without sacrificing any properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Palm‐based bio‐composites hybridized with kaolinite

This study described the mechanical and thermal properties of hybrid bio‐composites from oil palm empty fruit bunch (EFB) fibers and kaolinite. The polyurethane (PU) used as matrix is formed by reacting palm kernel oil (PKO)‐based polyester with crude isocyanate. The blending ratio of PU to EFB fibers was fixed at 35 : 65 and kaolinite was added at 0, 5, 10, 15, and 20% (by weight). The occurrence of chemical interactions between the hydroxyl terminals in both fillers and the PU system was determined via FTIR spectroscopy. Hybrid bio‐composites showed improved stiffness, strength, and better water resistance with the addition of kaolinite to an extent. At 15% of kaolinite loading, maximum flexural and impact strengths were observed. The interaction between kaolinite with PU matrix and EFB fibers enhanced the mechanical properties of the bio‐composites, which was justified from the FTIR spectrum. However, over‐packing of kaolinite was observed at 20% kaolinite loading, which ruptured the cellular walls and degraded strength of the bio‐composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Organic silicone‐modified transgenic soybean oil as bio‐based coating material for controlled‐release urea fertilizers

Novel bio‐based polyurethanes (PUs) were synthesized from transgenic soybean oil (TSBO) and then modified with hydroxyl‐terminated dimethyl silicone (HTMS) to coat urea prills for controlling nitrogen (N) release. Different kinds of coated ureas were prepared from these hydrophobic PUs. Physicochemical properties of the coatings were characterized in the laboratory. The N release characteristics of the PU‐coated ureas (PCUs) in water were determined at 25 °C. Experimental results showed that the presence of HTMS in the PUs reduced the coating porosity, increased the water‐contact angle of the coating material, and thus slowed the nutrient release from the PCUs. These results suggested that HTMS improved the structure and properties of coating materials for controlled release. These findings showed that bio‐based PUs derived from TSBOs made excellent coating material, particularly after HTMS modification, and thus may replace petroleum‐based PUs for controlled‐release fertilizers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44097.     

An overview of luminescent bio‐based composites

The development of inorganic/organic composite materials represents a fast‐growing interdisciplinary area in materials science and engineering. In this topic, a key idea is the production of composites comprising biopolymers and functional inorganic phases that could replace conventional materials in several high‐technology applications. Following this concept, the use of different polymers from renewable sources, such as cellulose, starch, alginate, and chitosan, have gained great relevance because of their renewable nature, potential biocompatibility, and biodegradability, as well as specific physicochemical properties. The combination of these biopolymers with different fillers (including inorganic nanoparticles (NPs), clusters, or ions) allows the design of innovative bio‐based materials with specific and/or improved properties, namely, optical, mechanical, and barrier properties, luminescence, and biological properties (as antimicrobial activity and biocompatibility). This review will focus on the most important synthetic approaches, properties, and applications of luminescent bio‐based composites obtained by combining different biopolymers and fillers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41169.