Making the Grade: Deciphering Particleboard Labeling

Long timber beams and boards may come to mind when one thinks of forest products, but not all wooden materials are created equal. Researchers from the Forest Products Laboratory (FPL) Wood, Fiber and Composites Research group are constantly working to refine technology used to create products that don’t necessarily fit the mold of traditional dimension lumber.

Particleboard is one such material. Itis produced by mechanically reducing the wood raw material into small particles, applying adhesive to the particles, and consolidating a loose mat of the particles with heat and pressure into a panel product.

The particleboard industry initially used cut flakes as a raw material; however, economic concerns prompted development of the ability to use sawdust, planer shavings, and sometimes even, mill residues and other waste materials.

Common wood elements used in wood-based composites from top left, clockwise: shavings, sawdust, fiber, large particles, wafers, and strands.

Common wood elements used in wood-based composites from top left, clockwise: shavings, sawdust, fiber, large particles, wafers, and strands.

This board can be used in a variety of applications, from furniture and flooring systems to paneling substrates and soundproofing.

To manufacture particleboard with good strength, smooth surfaces, and equal swelling, manufacturers  ideally use a homogenous raw material—though particleboard is readily made from virtually any wood material and from a variety of agricultural residues.

Low-density insulating or sound-absorbing particleboard can be made from kenaf core or jute stick. Low, medium and high-density panels can be produced from cereal straw. Rice husks are commercially manufactured into medium and high-density products in the Middle East.

Because material and production processes can vary, the quality and strength of the particleboard can as well. FPL handles the research, industry creates the product, but how does this knowledge get handed down to the consumer?

A grade mark on particleboard ensures that the product has been periodically tested for compliance with voluntary industry product performance standards. Inspection or certification programs also generally require that the quality control system of a production plant meets strict criteria. Particleboard panels conforming to these product performance standards are marked with grade stamps.

Examples of grade stamps for particleboard. (Courtesy of TECO, Sun Prairie, Wisconsin, and Composite Panel Association, Leesburg, Virginia.)

Examples of grade stamps for particleboard. (Courtesy of TECO, Sun Prairie, Wisconsin, and Composite Panel Association, Leesburg, Virginia.)

For more information, including additional examples and explanations of grade labeling for plywood, oriented strandboard (OSB) and sheathing, please refer to Chapter 11 of The Wood Handbook: Wood as an Engineering Material.

Documenting the Carbon Impact of Laminated Veneer Lumber Production

 

Laminated veneer lumber

Research Forest Products Technologist Richard D. Bergman continues his good work for the environment with a recent publication, Life-Cycle Inventory Analysis of Laminated Veneer Lumber Production in the United States.

Bergman’s study found that documenting the actual environmental performance of building products is becoming widespread and important because of concerns that some organization’s green-marketing claims are actually misleading. This is known as “greenwashing” in the business and borrows from the term whitewashing.

Developing environmental product declarations (EPDs) for building products is one way to provide scientific documentation that counters efforts to greenwash. Life-cycle inventory (LCI) data are the underlying data for subsequent development of life-cycle assessments (LCAs) and EPDs. EPDs are similar to nutritional labels for food.

This report follows data and reporting requirements as outlined in the Product Category Rules (PCR) for North American Structural and Architectural Wood Products and contains the LCI components for producing a North American EPD. At present, many EPDs for structural wood products made in North America exist. LCI compiles all raw material and energy inputs and outputs associated with the manufacture of a product on a per-unit basis within defined system boundaries. These boundaries can be limited to only one stage within the product life-cycle.

Multiple sequential LCI stages are usually combined to produce an LCA. LCAs describe the total environmental impact for a particular product. Many engineered structural wood products have been developed in the last several decades; for example, laminated veneer lumber (LVL ), which is comprised of many thin layers of dry wood veneers glued together with resins to form lumber-like products. LVL is designed to be used in the same manner as solid wood  products such as sawn lumber. Structural wood products such as LVL used in building construction can store carbon for long periods, which is typically greater or far greater than the carbon dioxide emissions released during manufacturing.

Environmental product declarations based on LCA data are an important means of documenting the environmental performance of building products. The International Organization for Standardization (ISO) requires that underlying LCI data be recent; this study updates the LCI data for LVL needed to develop an updated EPD. The amount of carbon stored in LVL exceeds total CO2 emissions during manufacturing by about 350 percent.

Cooperators include the USDA Forest Service Forest Products Laboratory, Madison, Wisconsin, and the Consortium for Research on Renewable Industrial Materials, Seattle, Washington.

Big Names Build Up with Recycled Product: Google, Whole Foods, and More Using ECOR

Green Building and Design Magazine recently featured an article on ECOR, a green building product developed in cooperation with the Forest Products Laboratory (FPL), and its growing popularity among some big name companies.

According to the article, “early adopters of ECOR include Google, Microsoft, Proctor & Gamble, Whole Foods, Starbucks, 20th Century Fox, Gensler, TOMS, and the list goes on.”

ECOR® gives architects and designers the freedom to create shapes and forms that would be impossible with traditional materials. Photo credit: JR Delia Photography

ECOR® gives architects and designers the freedom to create shapes and forms that would be impossible with traditional materials. Photo credit: JR Delia Photography

ECOR is made from 100 percent recycled material and is durable, 100 percent recyclable, and completely free of toxins. It is a design-friendly, high-performance composite material with a broad range of applications.

Most days you can find ECOR being produced right here at FPL (by Noble employees and under the terms of a specific agreement) while a larger ECOR production facility is under construction.

ECOR was previously featured on the USDA blog when the material was used to produce the first 100 percent sustainable studio set in Hollywood.

Cellulose Nanocrystals as Filler for Polymers

In a new publication, Supervisory Research Materials Engineer Gregory T. Schueneman reports on his research with cellulose nanocrystals (CNCs). CNCs are a class of renewable bionanomaterials with excellent mechanical properties that have attracted interest as filler for polymers. However, challenges associated with effective CNC dispersion have hindered the production of composites with desired property enhancements.

In Schueneman’s research, composites of polypropylene (PP) and low-density polyethylene (LDPE) with 5–10 wt% unmodified CNC are being produced for the first time with a solventless process, solid-state shear pulverization. Optical and electron microscopy revealed that the CNC dispersed very well and that degradation was strongly suppressed relative to composites made by melt mixing.

Field emission (FE) scanning electron microscope (SEM) images of as-received CNC at different weights.

Field emission (FE) scanning electron microscope (SEM) images of as-received CNC at different weights.

Taking thermal stability into account, this study has produced polyolefin/CNC composites with superior dispersion and property enhancements and has shown that CNC is an attractive and green filler for polymer composites. Over 50 million tons of plastic resins are used annually in the United States to manufacture products for a variety of end uses, including packaging, building materials, vehicles, furniture and furnishings, and electronics and electrical devices.

In this study, solid-state shear pulverization was used for the first time to produce composites of polyolefins and unmodified CNC. Microscopy and improved crystallization rate reveal excellent dispersion and suppression of CNC degradation within the polymer compared with composites made by melt mixing.These composites exhibit substantially greater stiffness, the greatest improvement ever reported for such composites made with unmodified CNC.

This study showed that CNC is an attractive and green filler for polymer composites.

The publication, titled “Cellulose nanocrystal/polyolefin biocomposites prepared by solid-state shear pulverization: Superior dispersion leading to synergistic property enhancements,” will be available online shortly. Cooperators include the USDA Forest Service Forest Products Laboratory, Madison, Wisconsin, and Northwestern University, Evanston, Illinois.

Key Research Publication: Short Cellulose Nanofibrils as Reinforcement in Polyvinyl Alcohol Fiber

A key FPL publication is Short Cellulose Nanofibrils as Reinforcement in Polyvinyl Alcohol Fiber by Ronald Sabo and Craig M. Clemons.

What is a nanofibril? Remembering that FPL is at the forefront of nanotechnology research, recall that nano means one billionth; for example, one nanometer is one billionth of a meter, or about the length that a fingernail grows in one second. A fibril is a fine fiber or filament.

nanofibril-17

Transmission electron microscopy image of (a cellulose nanofibril and (b short cellulose nanofibrils. The scale bar is 200 nm.

Cellulose nanofibril-based reinforcements constitute a new class of naturally sourced fiber-based reinforcements. Trees are one type of organism that forms nanofibrils and microfibrils from cellulose molecules to act as the main reinforcing elements within the organism. The high reinforcing potential of native crystalline cellulose within these fibrils led research cooperators from FPL and the University of Wisconsin-Madison to extract cellulose nanomaterials for use in composites.

Those researchers found some challenges to efficiently using cellulose nanomaterials as reinforcing fillers, and the use of water-soluble polymers is one way to avoid many of the challenges if they are carefully selected and appropriately used. One such polymer is polyvinyl alcohol (PVA), which is water-soluble, biodegradable, and biocompatible, and has been broadly investigated for applications including tissue scaffolding, filtration materials, membranes, and drug release. PVA is also used as a reinforcing fiber. Short cellulose nanofibrils (SCNFs) were mechanically isolated from bleached hardwood kraft pulp after being pretreated with enzymes and investigated as reinforcement for PVA fibers. These SCNFs are similar in appearance to cellulose nanocrystals (CNCs) but do not require concentrated sulfuric acid for their preparation.

Further optimization of enzymatic pretreatment will reduce energy requirements, cost, and environmental footprint. Adding small amounts of the SCNFs aided in alignment of the polymer during fiber preparation and improved the performance of the fiber. This work opens the door to strengthening and improving engineered composite materials.