Treesearch

Conferences covered in this semiannual review include the TAPPI Recycling Symposium and the 9th PTS/CTP Deinking Symposium. The intent of this feature is to present a synopsis of the significant research results and industry ideas related to paper recycling reported at these conferences. Due to space constraints, we are not able to cover all of the presented papers in detail. Readers are encouraged to obtain the original articles for more information.

Dehydropolymerization of [rho]-hydroxycinnamyl alcohols with manganese(III) acetate in either aqueous acetic acid or pyridine resulted in dehydropolymers (DHPs) that more closely approximate the structure of natural lignins than do DHPs produced by enzymic techniques. The 13C NMR spectrum of a "biomimetic" guaiacyl-DHP (G-DHP) from coniferyl alcohol was very similar to that of a lignin isolated from spruce wood, unlike a corresponding spectrum of a G-DHP prepared by a conventional enzymic technique. A similar comparison between a biomimetic guaiacyl/syringyl DHP (GS-DHP), a conventional...

The work described in this paper culminates an investigation into the treatability of five Appalachian hardwood species. Previous papers have described work using the waterborne preservatives CCA-C and ACQ-B. This paper details the results of pressure treatment with creosote and Timbor®. Six-inch long nominal two-by-four samples of red maple, yellow-poplar, red oak, hickory, and beech were end-sealed and vacuum/pressure treated. Two borate treatments were tested: wrapped in plastic or not wrapped. Measurements were taken of minimum and maximum penetration, percentage of cross-sectional...

A new instrument and technique developed at the USDA Forest Service, Forest Products Laboratory to evaluate the adhesion of inks on paper was used to study toner loss on copier papers. This instrument creates a fold with a very small radius in the printed region of a paper specimen. This fold is repeatedly rolled through the specimen until the desired degree of wear is induced. If the radius of the fold is small enough, a critical strain is reached where the toner layer fractures cohesively. Subsequent cycling will cause adhesive failure of the toner as fragments are peeled from the paper...

Preliminary figures of wood-based panels consumption in Europe show a small increase in 1999 to 52.1 million m3 a new record level. However, according to the European Panel Federation (EPF), real consumption taking into account particle board stock changes, was higher due to the recovery of markets in the second half of 1999. Particle board is the main panel in Europe with over 67% of total consumption. Consumption of MDF and OSB set record levels. MDF was up 10.7% to 7.14 million m3 and OSB increased by 43% to just under 1 million m3. In North America trends show a continued strong...

Consumption of wood fiber in pulp, paper and paperboard increased in the United States over the past century and is projected to increase well into the next century at a decelerating rate of growth. Harvest of pulpwood on forest land is the single largest source of wood fiber, followed by recycled paper and wood residues. In the past decade, wood residues declined in supply while use of recycled paper increased rapidly. Use of recycled paper is projected to increase more steadily in the future with slower growth in paper recovery for recycling. Harvest of pulpwood on forest land is...

Wet air oxidation (WAO) reactions of cellobiose, phenol, and syringic acid were carried out under mild conditions (155°C; 0.93MPa 02; soluble catalyst, Na5[PV2Mo10O40]). Initial oxidation rates were rapid but decreased to small values as less reactive oxidation products accumulated. Recalcitrant oxidation products were consumed more rapidly, however, if additional cellobiose or phenol was added, a procedure equivalent to recirculation of WAO-reactor effluent. A half-fraction, factorial investigation was used to correlate rate enhancement with individual experimental variables: using a...

The melt viscosities and mechanical properties of 3 different natural fiber-polypropylene composites were investigated. Coir (coconut), jute, and kenaf fibers were compounded with polypropylene at 30% by weight content. A capillary rheometer was used to evaluate melt viscosity. The power-law model parameters are reported over a shear rate range between 100 to 1000 s–1. Effects on melt viscosity with the use of a coupling agent and different fiber types were also evaluated.

Sisal fibers and finely powdered high-density polyethylene were surface functionalized using dichlorosilane (DS) under R-F plasma conditions to improve interfacial adhesion between the two dissimilar substrates. The functionalized polyethylene (70%) and sisal (30%) were compounded on four different ways using thermokinetic mixer and injected molded into composites specimens for test. Some improvements in mechanical properties of the composites due to the plasma treatments were achieved. Scanning Electronic Microscopy (SEM) data indicated that some compatibilization of the two plasma...

In recent years, a number of clear wood finishes have been developed that protect wood while accentuating its natural beauty. The focus of this publication is on those finishes having little visible pigment. In some cases, the pigments are included but are finely ground to create a coating that is transparent to visible light. Most natural clear wood finishes are designed to protect and beautify wood. Although this may sound simple, manufacturer’s claims that products protect, preserve, seal, last longer, work better, and spread farther than competitors’ products can be confusing. In fact,...