M. H. Freeman’s research while affiliated with Louisiana State University and other places

This paper focuses on the wood preservation aspects of copper based biocides. Included in this review are the following: Above ground and ground contact efficacy, permanence in above ground and ground contact uses, soil and water contact leaching, effects on wood properties and certain fixation aspects of copper systems. Previously unpublished data on the new micronized/dispersed copper based wood preservative systems are also included. These micronized systems now dominate the U.S. residential treated wood market which in turn accounts for roughly 50 percent of global wood preservation usage.

The initiatives to develop the wood preservation industry are discussed. The article also describes the growth of the industry since 1830s. Wood is a renewable natural resource, which is preservative treated to ensure structural integrity in many exterior applications. Arsenically treated wood cannot be used for residential purposes in the US and Canada.

Copper-naphthenate-treated poles in service were inspected for deterioration, pen- etration,retention, andserviceabi1ity.Thestudyincludedpolesinall hazardzonesin the United States. Poles installed by 12 different utilities and treated by 8 different treating companiesareincludedin thesurvey. BothsouthempineandDouglas-firpolesanddis- tribution and transmission poles are included in the survey. Only two of the surveyed poles were considered failures, indicating that properly treated copper naphthenate poles are performing satisfactorily.

The reduction of copper from cupric (Cu2+) to cuprous (Cu1+) form in post-steamed copper naphthenate-treated southern pine was monitored. The amount of cuprous oxide formed after the post-steam treatment was determined by X-ray diffraction (XRD). About 50% of copper was reduced from cupric to cuprous in post-steamed samples treated to a retention of 0.31 to 0.51% total copper. Less than 15% of the copper was reduced to cuprous in the post-steamed samples containing 0.71% total copper. Environmental scanning electron microscopy (ESEM) was used to collect images of the crystalline cuprous oxide deposits on the wood cell walls.

A study was conducted to evaluate the effect of oil type on the performance of test posts treated with oil-penta and exposed in DeQueen, AR for forty years in ground contact. The original assays for the poles were done by lime ignition, a practice used sparingly today in treating plants or by independent inspectors, in part due to the complicated analysis procedure and chances for error. XRF instruments for chlorine analysis have become commonplace. The question put forward by many inspectors, agencies, and treaters is 'Will XRF accurately predict lime ignition results?'. This study encompassed seven different oil systems. Regression analysis yielded an R2 value over 97% when using XRF to predict lime ignition values. The only caveat was that a proper calibration standard was required for the XRF analysis. Users should be confident that properly derived XRF values will match lime ignition values within 5%.

This study examines the influence of pre -treatment and post-treatment steaming on the character and physio-chemical nature of copper naphthenate in hydrocarbon solvent treated pine in larger, pole diameter, pole stub-length samples. This work is the continuation of two projects that began almost a decade ago. Previous reports indicated that certain morphological changes might occur in small laboratory steamed samples of copper naphthenate treated southern pine. Toluene-methanol extraction, UV-Vis spectroscopy, X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM) were used to investigate the nature and properties of the copper naphthenate present in the wood after 12 years of exposure. The formation of solid cuprous oxide occurred regardless of pre- or post- steaming conditioning.

Naphthenates have been used for the preservation of timber and cellulose since their original identification in Russia in the early 1880's as part of a series of petroleum characterizations. Later work in the development of copper naphthenate as a heavy-duty preservative for poles led to the development of various treating cycles similar to other oil- borne systems. Recent work concerning the post treatment steam conditioning of copper naphthenate treated southern pine has determined that some amorphous copper naphthenate is converted to a crystalline cuprous oxide. In small laboratory tests, this was later determined to be less efficacious than copper naphthenate. This paper reviews the performance of actual pole-diameter stubs placed in a high hazard location containing both termites and potential for early decay attack. Various treating cycles were used to treat the pole stubs in this test including various post-treatment conditioning methods.