Cottonseed & Corn Oil: PUR Stuff

Cottonseed used to be among the most useless of agricultural byproducts, until the industrial age figured out what it could do with cottonseed oil. Gradually, more and more uses were found for the oil, and now it and corn oil are being studied as sources of biobased polyols for making polyurethane (PUR), as described in a recently published paper. (This paper is one of the articles in the new special issue of the Journal of Renewable Materials, which contains a selection of papers presented at the 5th International Conference on Biobased and Biodegradable Polymers (BIOPOL-2015), held in Spain last October.)

A_pyramid_of_cotton_seed,_Florida,_by_Kilburn,_B._W._(Benjamin_West),_1827-1909_2

A 19th-century stereoscopic image of “a pyramid of cotton seed” in Florida (image from commons.wikimedia.org).

Various vegetable oils (VOs) and natural oil byproducts have been turned into polyols for PUR (see, for example, the April 13 JRM Blog posting here). For cottonseed and corn oils, “the fatty acid profiles of both VOs provide them the potential as raw materials for the replacement of petroleum-based building blocks and monomers,” note the new JRM paper’s authors, three of which are based in Mexico. “In addition, corn and cotton crops are a highly social culture in Mexico, generating direct and indirect labor, as they are able to produce a high number of original products and by-products from their manufacturing…”

The researchers converted the two oils into polyols and reacted them with 4,4′-methylene diphenyl diisocyanate (MDI) and hexamethylene diisocyanate (HDI) to make PUR. FTIR spectroscopy and thermal analysis were performed to compare the different polyols and the resulting PURs. Thermal analysis (DSC), for instance, revealed that the choice of isocyanate influences glass transition temperature, making some PURs more rigid than others at or above room temperature.

Overall, as the authors conclude, “Polyurethanes synthesized by using both types of biobased polyols and HDI and MDI showed homogeneous and nonporous morphologies with high thermal stability.”

Again, for readers who missed attending BIOPOL-2015: Volume 4, number 3 of the JRM, filled with papers from the conference, will soon be released; check for the new papers here.


Scrivener Publishing has just released a new book on renewable materials—Lignocellulosic Fibers and Wood Handbook, edited by Naceur Belgacem and Tony Pizzi. See its table of contents here.

You can also follow the “J Renewable Materials Blog” via Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

 

 

How Biodegradable is “Biodegradable”?

To say that a certain biopolymer “is biodegradable” is not enough—the statement needs to be qualified. The degree and mechanism of biodegradation needs to be determined through testing, since not all biopolymers degrade in the same way in composting or soil environments.

Shedding light on this are researchers in South Africa via a paper in the Journal of Renewable Materials. Our previous JRM Blog posting covered research on the bacterial copolyester poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), addressing how it biodegrades when it containes cellulose fibers. The study described below compares the biodegradation of PHBV apples-to-apples with that of poly(lactic acid) (PLA) and a PLA/PHBV (70/30 wt%) blend.

As the authors point out, biodegradation studies for these materials mainly have looked at weight loss from degradation and variations in morphology under different conditions; “however, they do not provide sufficient evidence on the final biodegradation step of polymeric carbon conversion into CO2, as well as its physical-chemical degradation process of the fragmented residues.” So their study also monitored the degree and rate of ultimate degradation (i.e., mineralization) in soil and simulated composting conditions using thermal and spectral analysis methods (DSC, TGA, FTIR and, SEM).

“This study provided important information with respect to microbial and enzymatic attacks and physical and chemical parameters involved in the biodegradation process” of the PLA, PHBV, and PLA/PHBV blend, they write. Probably the key observation is that the PLA and PHBV samples degraded much differently in soil than in composting conditions, where almost 90% of each sample was lost over time.

Muniyasamy et al (c)2016 Journal of Renewable Materials

“A real biometer flask respirometric system used for studying the biodegradation of polymeric materials.” (From Muniyasamy et al., (c)2016 Journal of Renewable Materials; new reuse without permission.)


Looking at CO2 emissions showed that the materials “have a short survival time under controlled composting,” in comparison to burying them in soil. In soil, all the materials struggled to degrade, though PHBV was the hands-down winner over PLA: PLA, PLA/PHBV, and PHBV showed, respectively, 4%, 32%, and 35% biodegradation.

The thermal, spectroscopic, and microscopic analyses helped show how much the “microbial systems” in composting provided a suitable biodegrading environment, compared with soil burial. For example, FTIR spectra indicated which chemical functional groups were being attacked by microbes degrading PLA and PHBV materials. Results showed that during composting, microbes are a factor in the hydrolytic degradation of carbonyl ester and carboxylic groups of the biopolymers. “Hydrolytic chain scissions at multiple locations in the heterochain polymer produce smaller molecules or oligomers, which can easily permeate out of the polymer matrix” and be further assimilated by microbes, the authors of the study note in the results.


Scrivener Publishing has just released a new book on renewable materials—Lignocellulosic Fibers and Wood Handbook, edited by Naceur Belgacem and Tony Pizzi. See its table of contents here.

You can follow the “J Renewable Materials Blog” via Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

 

Purified Cellulose Fibers Shore Up PHBV Biopolyester

Biodegradable biopolyesters show some great properties—except in some important ways, like at higher temperatures. The trick is to add components to them to improve weak properties without sabotaging their biodegradability.

As researchers in Spain point out in the new issue of the Journal of Renewable Materials, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), a bacterial copolyester from the polyhydroxyalkanoate (PHA) family, shows a lot of promise. It “has gained a lot of attention, especially in the packaging field, because of its renewable and non-food-competitive origin, biodegradability, and performance close to that of some commodity polymers [ref, ref].”

PHBV has mechanical properties similar to polypropylene’s, oxygen and aroma barriers similar to PET’s, and a better crystallinity and glass transition temperature for higher-temperature applications than its fellow biopolyester PLA. “Nevertheless, PHBV experiments show inferior mechanical performance at temperatures above 80°C, and its high price handicaps its use in low-cost applications [ref],” the authors note.

To improve its heat-affected properties, some kind of reinforcing filler could help—though it should be natural and biodegradable. “[T]he usage of natural fibers as fillers in polymer composites would allow the use of byproducts or residues from the agricultural and agroalimentary industry.” Fibers from cellulose and its derivatives can improve properties and even reduce costs of using the pricey PHBV, the researchers add.

So they studied PHBV samples loaded (at 3 to 45%) with “purified alpha-cellulose”—refined lignin- and hemicellulose-free fibers from wood-pulp manufacturing. These modified fibers reportedly can process at higher temperatures, are smaller and more homogeneous, and have higher properties than unmodified cellulose.

Estefanía Lidón Sánchez-Safont et al (c) 2016 Journal of Renewable Materials

“SEM micrographs of cellulose fibers and PHBV/cellulose composites: (a) cellulose low magnification (150x), (b) cellulose high magnification (550x), (c) PHBV-3C (500x), and (d) PHBV-45C (500x).” (From Estefanía Lidón Sánchez-Safont et al., image ©2016 Journal of Renewable Materials.)


The PHBV composite samples’ mechanicals and other properties (including compostability) were compared. They found that the cellulose content increased the storage modulus. “This reinforcing effect was especially pronounced at high temperatures,” they note. And the composites did indeed, as expected, disintegrate under composting conditions.

Estefanía Lidón Sánchez-Safont et al (c)2016 Journal of Renewable Materials

“Visual aspect of PHBV and PHBV/cellulose samples after 0, 28, and 42 days under composting conditions.” (From Estefanía Lidón Sánchez-Safont et al., image ©2016 Journal of Renewable Materials.)

Get the full paper here.


Also see Scrivener Publishing’s new Biodegradable and Biobased Polymers for Environmental and Biomedical Applications, edited by Susheel Kalia and Luc Avérous. The book has contributions from experts in fields related to biodegradable and biobased polymers and their environmental and biomedical applications; see its table of contents here.

You can follow the “J Renewable Materials Blog” via Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.


Another Kind of Renewable Component for PUR Foams

A polyurethane (PUR) foam can be made partly bio-based by using a biopolyol as one of its building blocks, as discussed in the previous blog posting here (and elsewhere). There’s even some research into using bio-based isocyanates as PUR’s other major chemical component. But what about using other kinds of renewable materials in PUR foams, like bio-based fillers?

This was part of an investigation in an article in the Journal of Renewable Materials. The researcher-authors compared a flexible PUR foam made with 20% rapeseed oil-based polyol compared to a petrochemical PUR foam loaded with a cellulose powder filler.

Bio-fillers have shown they can reinforce the “porous three-dimensional structure of open cell polyurethane foams” [ref, ref], the authors note. So in their work, the researchers loaded ultrafine cellulose powder into a PUR formulation at a rate of 3 parts per hundred parts of polyol using a “mixing-dosing device equipped with a static-dynamic mixer.”

Aleksander Prociak et al (c)2016 Journal of Renewable Materials

“SEM images of foam with cellulose cross section: (a) perpendicular and (b) parallel to foam rise direction” (image from Prociak et al., ©2016 Journal of Renewable Materials; no reuse without permission).


They were particularly interested in how the isocyanate index of their formulations affected foam properties. The isocyanate index (NCO) is one of many factors that affects foam density, resilience, strength, cell size, and so on. In short, it’s the “amount of isocyanate used [in a formulation] in relation to the theoretical equivalent amount,” the authors explain. “The NCO index is an important parameter which determines the amount of isocyanate groups in a polyurethane formulation.”

In this study, the isocyanate index did influence some properties, like the resilience (elasticity) of the foams, but not others—and not always the same properties in the same way for the biopolyol and bio-filler foams. The filler had some influence; for example, the filler apparently “can reinforce the porous structure of flexible foams, and with the increase of NCO it may give a synergistic effect with the polyurethane matrix, so that the material acts like a spring.”

Observations like this “is why further study should be applied in order to assess how the foam’s properties may change when higher concentrations of renewable components are applied,” they conclude.

This is the final JRM Blog posting about papers from the Journal of Renewable Materialsspecial issue on the Green Chemistry and Nanotechnologies workshop held last year in Portugal. Look for this blog’s next posting (on May 11) to cover a paper form the JRM’s newest issue, released this month.


Also see Scrivener Publishing’s new Biodegradable and Biobased Polymers for Environmental and Biomedical Applications, edited by Susheel Kalia and Luc Avérous. The book has contributions from experts in fields related to biodegradable and biobased polymers and their environmental and biomedical applications; see its table of contents here.

You can follow the “J Renewable Materials Blog” via Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.


 

“Tall Oil” Bio-Polyols for Auto-Worthy PUR Rigid Foams

Flexible polyurethane (PU or PUR) foams are literally all around you inside an automobile, beneath you in seating, overhead in the headliner, and sometimes in the door panels. Some of these foams are already being made using bio-based polyols.

But strong, rigid PUR foams also have roles to play in creating lightweight vehicle structures—and these too can be made using plant-oil-based polyols. This was the focus researchers in Eastern Europe reported on in the “Workshop on Green Chemistry and Nanotechnologies” issue of the Journal of Renewable Materials.

“Good quality polyols have been obtained from different vegetable oils like rapeseed oil (RO), castor oil, palm oil and especially soybean oil …,” the authors note, citing multiple sources. “Most of these oils are used already to produce a PU material feedstock on the industrial level.” As well as providing a competitive alternative to petroleum-based polyols, vegetable-oil polyols can lend hydrophobicity to a PUR formulation, they add [ref].

But most of the vegetable oils used industrially are “first generation” renewable materials, meaning theoretically they compete with food crop production. Any alternatives? “Tall oil” (TO) might be one—it’s a byproduct of cellulose production from forest biomass—“a mixture of fatty and rosin acids” and, as the authors point out, not an agricultural product.

So they made TO-polyol-based PUR and rapeseed oil-based PUR samples for FTIR spectroscopic characterization and physical testing. For comparison, they also made a PUR sample using a biopolyol made via the glycolysis of PET (specifically, recycled beverage bottle polyethylene terephthalate polyol, branded as Neopolyol or “Neo” polyols). Their main objective was to come up with “a material that would be used as a structural foam material for lightweight vehicles.”

Kirpluks et al (c)2016 Journal of Renewable Materials

“PU foams from RO/TEOA polyol” (left) and “PU foams from recycled PET (Neo 380)” (Images ©2016 Journal of Renewable Materials; no reuse without permission.)


The results? “This study has shown that polyols from renewable and recycled resources are a viable option for production of high-density rigid PU foams.” The bio-polyol foams had a renewable content of up to 19%, though they did not provide the same properties as the PET-polyol foam, given their larger foam cell sizes. But all foams showed thermal properties that would allow them to be used in production vehicles.

FTIR analysis showed that more research will be needed on catalysts and curing parameters, the researchers conclude. But new high-density rigid PUR foams like these ultimately “could be used as core material[s] for crash absorption,” like in vehicle crash beams.

Get access to the full article here.


Also see Scrivener Publishing’s new Biodegradable and Biobased Polymers for Environmental and Biomedical Applications, edited by Susheel Kalia and Luc Avérous. The book has contributions from experts in fields related to biodegradable and biobased polymers and their environmental and biomedical applications; see its table of contents here.

You can follow the “J Renewable Materials Blog” via Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

Scavenging for Formaldehyde with Soy Protein

Excess formaldehyde in laminated flooring (and its potential health effects) has been much in the news lately. (Meanwhile, estimates about the risk of cancer caused by long-term exposure to formaldehyde have recently been tripled.)

But the basic concerns aren’t new—the release of unreacted formaldehyde has always been an unpleasant side-effect of using resins like urea-formaldehyde (UF) for bonding wood-based products. Thus, green-minded researchers are looking for ways to reduce formaldehyde emissions from UF materials.

According to researchers in Portugal, “lowering the molar ratio of formaldehyde to urea (F/U) of the resins” is insufficient to meet new lower-formaldehyde standards [ref]. “Thus, new efforts have been made to deal with this challenge. The use of formaldehyde scavengers both in the synthesis of resins and in the production of wood-based panels has been one of the most studied methods [ref].”

They studied the use of soy protein as a formaldehyde scavenger in UF particleboard. Their work is reported in February’s “Special Issue from the 6th Workshop on Green Chemistry and Nanotechnologies” of the Journal of Renewable Materials.

First they prepared UF resins in three steps, incorporating soy protein in aqueous solution in each step, resulting in a net 5-15% soy protein in the dry resin for creating pressed particleboard samples for testing. They also tried adding 5-15% soy protein to the core layer during the production of the panels. They created a design of experiments to consider the effects of using soy protein at each step of the process.

Adding soy protein directly to the core panel layers resulted in some reduction of formaldehyde, without losses of internal bond strength, they found. Additions of soy at other stages of the UF resin production produced similar but unique changes (i.e., strength properties are not unaffected).

Flávio Pereira et al Natural Additive for Reducing Formaldehyde Emissions (c)Journal of Renewable Materials

“Formaldehyde content (mg/100 g oven dry board) of particleboards produced with soy protein powder in the core layer.” (From Flávio Pereira et al.: “Natural Additive for Reducing Formaldehyde Emissions,” ©2016 Journal of Renewable Materials.)


Overall, “The incorporation of a natural compound, soy protein, either in powder form in the blending process or in solution during resin synthesis, can contribute to a decrease in the formaldehyde content of particleboard panels,” they conclude. Further work is needed to look at “real changes” in the polymer structure, but “it appears that soy protein can bind chemically with free formaldehyde, effectively acting as a formaldehyde scavenger, without sacrificing the physical properties of the resulting panels.”


See Scrivener Publishing’s new Biodegradable and Biobased Polymers for Environmental and Biomedical Applications, edited by Susheel Kalia and Luc Avérous. The book has contributions from experts in fields related to biodegradable and biobased polymers and their environmental and biomedical applications; see its table of contents here.

You can also follow the “J Renewable Materials Blog” on Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

Biopolymer Xerogels

Xerogel is not an everyday household word, even for people working in science and engineering. It denotes a kind of potentially useful super-porous materials similar to an aerogel. (At least one reviewer describes the difference between them this way: unlike with aerogels, in a xerogel’s creation, the liquid phase in the gel is eliminated by evaporation, leaving shrinkage cracks in its structure. A hydrogel is a water-based gel, which can be turned into a xerogel; hydrogels are finding applications in sensors, separation membranes, adsorbents, and drug-delivery systems [ref].)

The same goes for itaconic acid, an unsaturated dicarboxylic acid produced via sugar fermentation; it’s not commonly spoken of as renewable polymer precursor, but it was one of the U.S. Department of Energy’s twelve biobased “platform chemicals” identified in 2004 as having the greatest potential for industrial use (ref [pdf]). As one industry commentator puts it, “Itaconic acid is seen as a highly interesting chemical building block due to its resemblance to maleic acid, a compound commonly used in acrylates and resins” (Plastics Engineering, March 2016, p. 19).

A team of researchers from Cracow University of Technology in Poland is putting these two options together by creating itaconic acid-based biopolymer hydro-xerogels using a deep eutectic solvent (DES [pdf]). Their work is reported in February’s “Special Issue from the 6th Workshop on Green Chemistry and Nanotechnologies” of the Journal of Renewable Materials.

They used a DES with choline chloride to prepare an itaconic acid-based hydrogel that was then lyophilized (i.e., freeze-dried) into a xerogel. Samples prepared with and without polyethylene glycol (PEG) as an inert dilutent were studied for their morphology (using scanning electron microscopy (SEM)) and copper ion uptake.

Szczepan Bednarz et al (c)2016 Journal of Renewable Materials

“SEM micrographs of xerogels prepared in DES in the presence of PEG” (Szczepan Bednarz et al. ©2016 Journal of Renewable Materials; no reuse without permission).


“Depending on the crosslinking amount and synthesis protocol used, it is possible to prepare materials with different availability of carboxylic groups, morphologies and specific surface area,” the authors explain.

“The materials have many possible applications,” they conclude. “The copper uptake achieved suggests the potential use of the xerogels to remove heavy metals from wastewater.”

Moreover, the reagents are nontoxic, so “the hydrogels/xerogels prepared in the DES could be considered as solid supports for immobilization of microbial cells and/or enzymes.”


See Scrivener Publishing’s new Biodegradable and Biobased Polymers for Environmental and Biomedical Applications, a book edited by Susheel Kalia and Luc Avérous. The book has contributions from experts in fields related to biodegradable and biobased polymers and their environmental and biomedical applications; see its table of contents here.

You can also follow the “J Renewable Materials Blog” on Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

Gelatin from Tannery Wastes

Waste byproducts that interest renewable materials researchers usually come from plant-product processing, but animal processing produces its own potentially useful waste materials. Tannery wastes from hide processing in particular are being targeted by European government regulators: “Member States are required not only to take measures in order to minimise waste production by developing clean technologies, but also to encourage their recovery and valorization,” note researchers from footwear research center INESCOP, in Spain.

Looking to turn tannery wastes into useful co-products, the INESCOP researchers report work on the creating gelatin (alternate spelling: gelatine) from them for microencapsulation applications, “a coating technology by which active substances are coated in a polymeric shell, leading to core-shell particles called microcapsules.” Their work was published in February’s “Special Issue from the 6th Workshop on Green Chemistry and Nanotechnologies” of the Journal of Renewable Materials.

M.A. Pérez-Limiñana et al. Influence of the Extraction Temperature (c)2016 J Renew Mater

“Microcapsules obtained by complex coacervation” from M.A. Pérez-Limiñana et al., ©2016 Journal of Renewable Materials.

Gelatin, “a soluble protein obtained by partial hydrolysis of collagen,” can be extracted from untanned solid waste in several steps, using the right conditions, producing a material with the properties for microencapsulation. Typical steps include an alkaline collagen pre-treatment, which produces a lot of wastewater and can take a lot of time. However, “enzymatic pre-treatment opens up a new alternative to the alkaline pre-treatment to reduce processing time and wastewater,” the authors explain.

They analyzed gelatins produced from bovine pelt wastes at different extraction temperatures and determined their chemical compositions and molecular weights. One key property for analysis was the gel strength (or “Bloom value”), which determines the quality of the gelatin.

Optimized enzymatic pre-treatment and extraction temperatures “allow medium-grade gelatines to be obtained with suitable properties for microencapsulation applications,” they found. “The extraction temperature determines gelatine yield, gelatine properties and, therefore, its microencapsulating ability.” More work is being carried out to produce high-grade gelatins from tannery wastes, they add.


Scrivener Publishing has released two volumes of Functional Polymers in Food Science: From Technology to Biology, edited by Giuseppe Cirillo, Umile Gianfranco Spizzirri, and Francesca Iemma. Click here to see Volume 1’s table of contents.

You can also follow the “J Renewable Materials Blog” on Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

Cashew Nutshell Liquid for “Hybrid” Coatings

Somewhat analogous to the coriander seed press cake that was the subject of last week’s JRM Blog posting is cashew nutshell liquid (CNSL), an inedible byproduct of cashew production. CNSL is flexible in the ways in which various resins can be created from it. (Longtime followers of this blog might remember our discussing the use of CNSL-based polycardanol as a flame retardant, from a study in the Journal of Renewable Materials in 2013.)

A sophisticated tack was taken in a new JRM study by researchers at the Institute of Chemical Technology in Mumbai, India (a country that happens to be a major producer of cashews). The focus was on creating a “hybrid” polymeric coating based on CNSL, as an alternative to non-bio-based, conventional metal coatings (for stoving, for example). Here, sustainability comes not just from the CNSL but also from “sol-gel chemistry, as an eco-friendly alternative to conventional surface pretreatment,” they explain.

“For almost 10 years, sol-gel derived organic-inorganic hybrid coatings have emerged as an eco-friendly surface protection methodology for metals,” the authors note [ref].

Sol-gel reactions include an inorganic component, and in this case a silane was used to modify the CNSL, leading to a “functionally reactive CNSL-based hybrid sol.” In the resulting cured coating, “a three-dimensional network of siloxane (–Si–O–Si–) linkages helps to impede the ingress of aggressive chemicals through the coating.”

Balgude and Sabnis (c)2016 Journal of Renewable Materials

“Schematic representation of synthesis of CNSL-based hybrid sol” (from Balgude and Sabnis, ©2016 Journal of Renewable Materials; no reuse without permission).


The hybrid sol was added to a conventional alkyd-melamine formaldehyde-based stoving system. The mixture was applied as a coating to milled-steel panels, and cured. The panels were put through a range of tests: spectroscopic, optical (gloss), chemical, mechanical, thermal, electrochemical (corrosion), morphological, and weatherability (i.e., ultraviolet light-resistance testing).

The hybrid sol content improved some mechanical and chemical-resistance properties. And the coatings showed “good balance between flexibility and hardness properties.” Overall, “we concluded that the developed CNSL-based hybrid sol can be successfully explored in conventional stoving systems with improved performance,” the authors state.

See the abstract of the paper here.


Scrivener Publishing just released two volumes of Functional Polymers in Food Science: From Technology to Biology, edited by Giuseppe Cirillo, Umile Gianfranco Spizzirri, and Francesca Iemma. Click here to see Volume 1’s table of contents.

You can also follow the “J Renewable Materials Blog” on Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.

Coriander Press Cake for Protein-Bound Fiberboard

There are two goals that renewable-materials researchers often seek to fulfill: (1) when possible, make useful materials from waste biomass (like food-processing byproducts) rather than valuable agricultural commodities themselves, and (2) investigate uses for all the components of natural materials, whether they are (as this blog has covered just in the last couple months) plant fibers, oils, dyes, or starch.

In the JRM paper covered in this posting, plant protein plays the key role. And it’s from the source of a spice loved by millions of people the world over: coriander seeds.

Coriander seeds public domain pic from pdpics-dot-com

Coriander seeds (public domain picture from pdpics.com).


Researchers in Europe looked at what could be done with the press cake left over after useful oils have been extracted from coriander fruit. “[A]s renewable resources containing both proteins and fibers, the press cakes could be considered as natural composites, thus being usable for the production of biodegradable and value-added agromaterials through thermo-pressing.”

They molded fiberboards using the cake made from the pressing of coriander fruits in a single-screw extruder. The fiberboard samples were made via thermo-pressing in a mold at 160-200°C at various pressures and times, and then the samples were analyzed for various thermal and mechanical properties.

Given that “no organic compounds inside the press cake, especially proteins, were likely to thermally degrade during molding, even at 200°C,” the researchers found they could produce fiberboards with potentially useful mechanical properties. Though not degrading, protein in the press cake did appear to undergo a thermal transition that allowed it to serve as a “natural binder” for the surrounding plant fibers in the fiberboard, they explain. “Proteins acted as a binder inside the boards, leading to the production of cohesive panels inside which the fibers contributed to their mechanical reinforcement.”

Given the fiberboard’s flexural strength and relatively low water sensitivity, the material could “find applications in various industrial fields such as the handling and storage industry (interlayer sheets for pallets), the manufacture of containers or furniture, or the building trade (floor underlayers, interior partitions or ceiling tiles),” the authors propose.


Scrivener Publishing just released two volumes of Functional Polymers in Food Science: From Technology to Biology, edited by Giuseppe Cirillo, Umile Gianfranco Spizzirri, and Francesca Iemma. Click here to see Volume 1’s table of contents.

You can also follow the “J Renewable Materials Blog” on Twitter at @scrivpub.

Also online from the Journal of Renewable Materials: new “fast track” articles. You can sample an issue of the JRM, or acquire any article as an individual download. This blog’s moderator and editor is Mike Tolinski, author of Plastics and Sustainability.