AGRICULTURE ROOM
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DEVELOPMENT Of ADHESIVES WITH
IMPROVED HEAT RESISTANCE
IN COWS
or
STAINLESS STEEL
July 1961
No. 1883
This Report Issued in Cooperation
with the Bureau of Naval Weapons,
Department of the Navy
FOREST PRODUCTS LABORATORY
MADISON 5, WISCONSIN UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
in Cooperation with the University of Wisconsin
•
DEVELOPMENT OF ADHESIVES WITH IMPROVED HEAT
RESISTANCE IN BONDS OF STAINLESS STEEL!
By
J. M. BLACK, Chemist
and
R. F. BLOMQUIST, Chemist
Forest Products Laboratory, —
2 Forest Service
U.S. Department of Agriculture
Summary
Adhesives containing combinations of polyamide resin with melamine compounds, epoxy resins with vinyl anhydride copolymers, and inorganic fillers
were studied as heat-resistant bonding agents for stainless steel.
Attempts to improve the strength of the polyamide-melamine type adhesive
at 550° F. were unsuccessful.
Studies were made of the heat-resistant properties of eight different epoxy
resins modified with an ethyl acrylate-maleic anhydride copolymer and with
maleic anhydride. The most promising of these were adhesive formulations
of epoxy resins which were glycidyl ethers of either bisphenol A or tetra
hydroxy phenyl ethane and contained aluminum powder and arsenic pentoxide
fillers impregnated into asbestos cloth.
!This is the final report of an investigation made in cooperation with the
Department of the Navy, Bureau of Naval Weapons, under Order No.
NAer 01967.
Maintained at Madison, Wis., in cooperation with the University of
Wisconsin.
Report No. 1883
Introduction
The objective of this project was to develop heat-resistant adhesives for bonding stainless steel, based on (a) polymers of polyamide combined with melamine compounds, and (b) vinyl copolymers, containing reactive anhydride side
groups, combined with epoxy resins.
The phenol-epoxy type of adhesive, generally recognized as one of the most
heat-resistant organic adhesives for metal bonding, possesses high tensile
shear strength at elevated temperatures when tested both immediately and
after relatively long periods of aging at temperatures up to 600° F. in bonds
of aluminum. One serious limitation of this type of adhesive, however, is the
low resistance to thermal aging on bonds of stainless steel at temperatures
of 500° F. and above.
Some results of the work at the U.S. Forest Products Laboratory for the
National Advisory Committee on Aeronautics3 showed that thermal aging
resistance of an adhesive bond was related to the chemical structure of the
polymer and the type of metal adherend. Thus phenol, epoxy, and phenolepoxy type adhesives had good thermal aging properties in bonds of aluminum
but were poor in bonds of stainless steel. Phenol-nitrile rubber and siliconetype adhesives, however, showed better thermal aging resistance in bonds of
stainless steel than in bonds of aluminum.
This study also revealed that the addition of certain inorganic compounds to
a phenol-epoxy type of adhesive improved the resistance of the adhesive to
heat aging on stainless steel. Some of these inorganic materials were compounds of manganese, arsenic, tin, and antimony. Later work by Janis and
others± on temperature-resistant adhesives for steel showed very promising
results with a silicone-epoxy-phenolic adhesive system cured with arsenic
pentoxide. A similar increase in resistance to thermal degradation and
increased joint strength were obtained with antimony trioxide in a phenolepoxy adhesive and straight epoxy-resin adhesive in bonds of aluminum.-53Black, J. M. and Blomquist, R. F. Development of Metal Bonding Adhesive
With Improved Heat Resistance. WADC Tech. Report 56-650. November
1956.
-Janis,
-Jani s, E. C., Boram, W. R. , Riel, F. J., and Sussman, S. E. Research
and Development on Elevated Temperature-Resistant Structural Metal-toMetal Adhesives. WADC Tech. Report 59-11. May 1959.
_Black, J. M., and Blomquist, R. F. Relationship of Metal Surfaces to HeatAging Properties of Adhesive Bonds. NACA TN 4287. September 1958.
Report No. 1883
-2-
6
NASA at the Forest Products Laboratory
Results of some further work —for
involved a study to relate the polymer structure of the base component of the
adhesive to thermal degradation in bonds of aluminum and of stainless steel.
This study was essentially a screening of a variety of basic polymers for
resistance to degradation at 550° F. and did not include investigations into
formulation variables of catalysts, fillers, or crosslinking agents directed
toward development of an improved heat-resistant adhesive. The results of
this work revealed some polymer systems which possessed a relatively high
degree of resistance to aging at 550° F. in bonds of stainless steel. These
promising materials were polyamide resins, butadiene copolymers, combinations of phenol resin with butadiene copolymers, melamine resin with
polyamides, and a combination of a maleic anhydride-vinyl copolymer with
epoxy resins.
The present study was undertaken to develop further the melamine-polyamide
and the vinyl anhydride copolymer-epoxy resin combinations into acceptable
heat-resistant adhesive formulations for bonding of stainless steel. Investigations of curing mechanisms, both organic and inorganic in nature, which
would increase strength at elevated temperature were to be considered.
Experimental Procedure
Polymer and Adhesive Materials
The various polymers employed in this study are designated by code numbers
in the test and tables of the report. They were dissolved in appropriate
solvents and were applied to the metal surfaces as solutions or suspensions
or impregnated into a woven asbestos cloth and applied as tape adhesive. The
asbestos cloth was type 28-PO-47, made by Raybestos-Manhattan, Inc. , and
was sized by immersion in A-1100, an organic silane solution made by Union
Carbide and Carbon, and dried for 30 minutes at 300° F.
The adhesive formulations of polyamide and melamine were dissolved in
methyl alcohol, isopropyl alcohol, and water systems to have a solids content
of about 20 percent by weight. Heating and refluxing of the materials was
employed to aid in dissolving the polymers. Solvents were removed before
bonding by oven-drying specimens at 200° F. The information on drying conditions, bonding temperatures, bonding time, and pressure is given in table 1
for the polyamide-based adhesives.
6 lack,J. M., and Blomquist, R. F. Relationship of Polymer Structure to
_33
Thermal Deterioration of Adhesive Bonds in Metal Joints. NASA TN D-108.
August 1959.
Report No. 1883
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In the epoxy resin-vinyl anhydride copolymer adhesive formulations, the
polymer materials were dissolved in methyl ethyl ketone with refluxing to a
solids content of about 10 percent. To aid in the solution of the copolymer,
it was reduced in the presence of methyl ethyl ketone to small particles in a
Waring blender before refluxing. The aluminum dust and arsenic pentoxide
also were mixed into the polymer solution by means of the Waring blender.
In making the asbestos cloth tape modifications of the adhesives, four heavy
coats of adhesive solutions were applied to the cloth by brush and dried for
10 minutes at 160° F. between coats and a final drying period of 10 minutes
at 200° F. after the last coat. Only one layer of the tape adhesive was used
in bonding. In bonding with the .solution-type adhesive, two coats of the epoxy
resin-copolymer solution were applied to each metal surface. Each coat was
dried for 10 minutes at 200° F. before pressing. All bonds of epoxy-resin
formulations were cured at 400° F. for 60 minutes at a bonding pressure of
400 pounds per square inch.
The aluminum filler employed in this study was aluminum dust, Alcoa 123
from the Aluminum Company of America. It was used as obtained. The
arsenic pentoxide, chemically pure, was dried at 200° F. and kept in a
dessicator until used.
Specimen Preparation and Tests
The tensile shear strength of 0.5 -inch lap-joint specimens of 16-gage, Type
316, 18-8 annealed stainless steel was employed as the means of evaluating
the bonding properties of the various formulations. Joints were tested at
80° F. and at 550° F. both before and after aging at 550° F. to determine
the resistance of the adhesive bonds to heat.
Test specimens were preparedbybonding 1- by 3.5-inch coupons into a lapjoint specimen with a 0.5-inch overlap. This resulted in specimens 1 inch
wide and 6-1/2 inches long. Preparation of individual specimens was done to
eliminate the problem of bond failure or partial failure during cutting of
specimens from a bonded panel. The annealed steel surfaces were prepared
for bonding by first immersing them in a solution of 100 grams of concentrated
hydrochloric acid, 4 grams of 30 percent hydrogen peroxide, 20 grams of
40 percent formalin solution, and 90 grams of water at 150° F. for 10 minutes.
After the surfaces were rinsed in tap water, they were immersed for
5 minutes at 150° F. in a solution consisting of 10 grams of concentrated
sulfuric acid, 1 gram of sodium dichromate, and 30 grams of water. Surfaces
were then rinsed in distilled water and air dried.
Report No. 1883
-4-
•
•
Twelve lap-joint shear specimens were prepared for each adhesive formulation. Three specimens were tested for each condition of test at 80° and
550° F. before and after heat aging. Test specimens were loaded in tension
in self-alining grips at the rate of 600 pounds per 0.5 square inch per minute.
Load was applied in the tests at the elevated temperature 5 minutes after the
specimen came to the test temperature as determined by thermocouple
measurements.
Temperature during heat aging was controlled within ±3° F. in special
electrically heated ovens.
DISCUSSION
Studies on Polyamide-Melamine Formulations
The results of tensile lap-shear tests are shown in table 1. The polyamide
(PA-1) employed in these studies was an alcohol-soluble type of nylon and was
combined with varying amounts of diallyl melamine, melamine-formaldehyde
resin (MF-1), and curing agents paraformaldehyde, maleic anhydride, and
triethylamine. Paraformaldehyde was included in the adhesive compositions
in an attempt to produce methylol groups on the diallyl melamine which could
react with the amino hydrogens of the polyamide to produce cross linkage.
In addition, there was also the possibility that the allyl groups could cross
link with each other after aging at high temperature or would be free to form
a strong bond to the steel surface. The triethylamine was considered to be
a catalyst for the methylolation reaction. Maleic anhydride also could conceivably form a cross link between methylol groups and reactive amino
hydrogen, and the unsaturated bonds would be potentially reactive with the
allyl groups.
The formulations with diallyl melamine were rather. similar in strength
properties regardless of amount of paraformaldehyde, triethylamine, and
maleic anhydride. Initial tensile shear strength at 80° F. ranged from about
1,700 to 2,600 pounds per square inch and, after aging 3 hours at 550° F. ,
ranged between 400 and 700 pounds per square inch. These formulations had
no strength at 550° F. either immediately or after 3 hours at 550° F. ,
indicating that little or no cross linkage had occurred.
Formulations combining a melamine-formaldehyde resin (MF-1) with the
polyamide showed some strength at 550° F. as increased amounts of the
melamine resin were used. Shear strength at 80° F., however, was decreased
Report No. 1883
-5-
as the melamine resin was increased, possibly indicating excessive embrittlement of the adhesive. Bond strength at 80° F. after heat aging was also low,
presumably because of the low resistance of the melamine resin to thermal
degradation and further embrittlement.
When melamine compounds were deleted from the formulations and the
polyamide was combined with maleic anhydride or paraformaldehyde either
separately or together, the strength of bonds at 80° F. was improved by
heating for 3 hours at 550° F., but no strength was obtained . at 550° F.
Because of the unsuccessful attempts to develop bond strength at elevated
temperature with these formulations, further work on the polyamide-melamine
combinations was discontinued.
Studies of the Epoxy-Resin-Vinyl Copolymer Formulati on s
In the epoxy resin-vinyl copolymer series of formulations, various epoxy
resins were combined with a vinyl copolymer (C-1) reported to be composed
95 percent of ethyl acrylate and 5 percent of maleic anhydride. An anhydride
equivalent weight of 2,000 grams was assumed for this copolymer in the
formulation studies. These combinations could conceivably produce cross
linkage through reaction of the epoxide and anhydride groups. In many formulations, additional molecular maleic anhydride was added to the formulation
to attain a particular ratio of epoxy equivalents to anhydride equivalents.
The epoxy resins employed varied in chemical structure. Resins of the bisphenol A, tetra glycidyl ether of hydroxyl phenyl ethane, Novalac epoxy,.
dicyclopentadiene dioxide, dicyclodiepoxycarboxylate, silicone-epoxy, and
unsaturated polyolefin types were employed.
Formulations with. Epoxy Resin, E-1
$poxy resin E-1 was a diglycidyl ether of bisphenol A with a reported epoxide
equivalent weight of 486 grams. The results of the tensile shear tests of lap
joints at 80° and 550° F. are shown in table 2 for the different formulations.
For solution-type adhesive formulations of E-1 resin with copolymer and
copolymer supplemented with maleic anhydride, the strength of bonds at
550° F. after 48 hours at 550° F. varied from 20 to 150 pounds per square
inch. The ratio of epoxy equivalent to anhydride equivalent in these formulations had no marked effect on joint strength at 550° F. At a ratio of about
1:1 of epoxide to anhydride equivalents, formulations with a combination of
copolymer and molecular maleic anhydride (adhesive No. 30B, table 2) were
Report No. 1883
-6-
•
•
higher in strength after aging at 550° F. than a formulation with copolymer
alone (adhesive No. 49, table 2) indicating the plasticizing effect of the large
amount of copolymer in relation to the amount of epoxy resin. The addition
of a polyhydric alcohol, glycerol, as initiator of the reaction between
anhydride and epoxide groups seemed to have no beneficial effect (adhesives
Nos. 37C, 43, and 30C, table 2).
The most striking improvement in strength of bonds at the elevated temperature after aging 48 hours at 550° F. was obtained when the asbestos tape
modification with aluminum powder and arsenic pentoxide fillers was employed.
The effectiveness of the aluminum powder and arsenic pentoxide fillers as
curing agents is shown from the results obtained with solution-type adhesives
Nos. 39A, 39B, and 35B, which were modifications without filler, and with
adhesives Nos. 39C, 39D, and 35D, which were modifications with the
aluminum and arsenic pentoxide in tape form.
Shear strength of the tape formulas at 550° F. was increased also as the
amount of anhydride employed was decreased. Adhesive tape-filler formulations in which the anhydride content was 0.27 equivalent or less to 1 mol of
the epoxide (adhesives Nos. 39D, 42, and 39C, table 2) were higher than
adhesives Nos. 35D and 23C. The formulation without anhydride (adhesive
No. 52) was slightly higher in strength after aging at 550° F. than any of the
other formulations, indicating no apparent advantage in the use of anhydride
compounds in the cure of the epoxy resin. All formulations of epoxy resin
were characterized by low strength at 550° F. after 3 hours at 550° F. This
was apparent for both the solvent and tape-filler modifications, indicating the
cure associated with the aluminum and arsenic pentoxide was a relatively
slow process and developed only after longer aging at 550° F.
Strength properties of the more promising type adhesives Nos. 39C, 39D,
and 52 at 80° and 550° F. after aging for 100 and 200 hours at 550° F. are
shown in table 3. These results show that only adhesive No. 52 without
copolymer or maleic anhydride modification retained any appreciable strength
at 550° F. (610 pounds per square inch). The results are significant in that
the use of aluminum and arsenic pentoxide as fillers serve not only to cross
link the epoxy resin but also to retard its thermal degradation in bonds of
stainless steel. Adhesive tape No. 52 had a strength of 2,532 pounds per
square inch at 80° F. after 3 hours at 550° F. (table 2), but was lower after
100 hours at 550° F. (1, 152 pounds per square inch, table 3), and after 200
hours at 550° F. had a tensile shear strength of 786 pounds per square inch
at 80° F.
The shear strength of the adhesive bonds at 80° F. for similar formulations
was generally higher after aging for 3 hours at 550° F. for the solution type
than for the corresponding filler -tape modifications.
Report No. 1883
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•
Formulations With Epoxy Resin E-2
Epoxy resin E-2 was a tetra glycidyl ether of tetrakis (hydroxyl phenyl) ethane
with an epoxide equivalent weight of 218 grams. Results of tensile shear tests
are shown in table 4.
Solution-type formulations of epoxy resin with copolymer or with copolymer
and maleic anhydride had shear strengths below 200 pounds per square inch
at 550° F. after aging 48 hours at 550° F. Joint strength at 550° F. was
decreased as the ratio of epoxide to anhydride was increased, for example,
from 1 to 0.175 in formulation 36A to a ratio of 1 to 1.05 in formulation 31B
(table 4). The addition of glycerol as a cure initiator in formulations 32B3
and 32B4 produced higher bond strength at 550° F. than similar formulations,
adhesives Nos. 32B2 and 36B, without glycerol.
Adhesive tape modifications with aluminum and arsenic pentoxide filler were
considerably higher in strength at 550° F. than the solution-type formulations.
All tape formulations had a tensile shear strength exceeding 400 pounds per
square inch at 550° F. after aging 48 hours. Shear strength after aging for
100 and 200 hours at 550° F. (table 3) were usually lower than after 48 hours
at 550° F., particularly for adhesive No. 31C (table 4) which had a high
amount of anhydride in the formulation. Bond strengths at room temperature
after aging 100 and 200 hours were significantly lower than after shorter
periods of heat aging.
Adhesive tape No. 51 (table 4) a formulation of the epoxy resin without
anhydride modification, had the highest strength at 550° F. of the E-2 resin
formulations with a strength of 794 pounds per square inch after 48 hours at
550° F. However, joint strength of this adhesive at 80° and 550° F. after
aging for 100 and ZOO hours (table 3) was much lower.
In adhesives 58 through 58-3, the amount of arsenic pentoxide was varied
from 8 to 32 percent. Joint strength at 550° F. after aging 48 hours was
increased to 732 pounds per square inch but strength after 3 hours' aging
was decreased as the amount of arsenic pentoxide was increased. These
results tended to indicate that the arsenic pentoxide may have retarded the
rate of cure, but contributed to the resistance of the adhesive to thermal
deterioration and greater degrees of cross-linking with higher shear strength
when cured adequately by longer aging at 550° F. The strength of lap joints
at room temperature was not changed appreciably by increasing the amount
of arsenic pentoxide in the formulation. The increased amounts of arsenic
pentoxide had no marked beneficial effect on resistance to long-time heat
aging, as seen from the results of shear tests at 550° F. after aging for 100
and 200 hours at 550° F. (table 3). Report No. 1883
-8-
•
•
Formulations with Epoxy Resin, E-3
Epoxy resin E-3 was a diglycidyl ether of bisphenol A with a reported epoxide
equivalent weight of 193 grams. The results of tensile shear tests of adhesive
formulations of this resin are shown in table 5. Bonds of the various formulations were low in strength at 550° F. after aging for 48 hours at 550° F.
No appreciable increase in strength was obtained when tape modification with
aluminum and arsenic pentoxide filler was used.
Formulations with Epoxy Resin, E-4
Epoxy resin E-4 was an epoxy Novalac-type resin with an epoxy equivalent
weight of 176 grams. Test results in table 6 show that shear strength of the
solution type adhesive at 550° F. after 48 hours at 550° F. was increased
moderately as smaller amounts of anhydride copolymer and maleic anhydride
were used. The most marked increase in strength at 550° F. after 48 hours
was obtained with the tape modification (adhesive No. 55) with aluminum and
arsenic pentoxide filler. The joint strength at 80° and 550° F. of bonds made
with this adhesive (No. 55), however, were decreased by aging for 100 or
200 hours at 550° F. (table 3).
Formulations with Epoxy Resin, E-5
Epoxy resin E-5 was a silicone-epoxy resin with an epoxy equivalent weight
of 174 grams. The tensile shear tests of various formulations with the
adhesive, shown in table 7, were low at both room temperature and 550° F.
except for adhesive formulation No. 54. Adhesive No. 54 was a tape modification with aluminum and arsenic pentoxide filler and had shear strengths of
about 1,000 pounds per square inch at 80° F. and about 400 pounds per square
inch at 550° F. after 48 hours at 550° F. The shear strength of bonds made
with adhesive No. 54 after aging for 100 and 200 hours at 550° F., table 3,
was appreciably lower than after 48 hours of aging. The marked increase in
strength with use of aluminum and arsenic pentoxide in the formulation No. 54
suggests that further study of these materials with epoxy resin E-5 may result
in even better strength properties and resistance to heat aging.
Formulations with E-6, E-7, and E-8 Resins
Results of bonding with adhesive formulations of epoxy resins E-6, E-7, and
E-8 are shown in table 8. Resin E-6 was a dicyclopentadiene dioxide epoxy
monomer with a reported epoxy equivalent weight of about 82 grams. Resin
E-7 was a dicyclodiepoxy carboxylate monomer with an epoxy equivalent
Report No. 1883
-9-
weight of about 140 grams. Resin E-8 was an unsaturated polyolefin with an
epoxy equivalent weight of about 145 grams.
An adhesive tape formulation of resin E-6 with copolymer, maleic anhydride,
glycerol, aluminum, and arsenic pentoxide, (adhesive No. 47B, table 8) had
higher strength at 80° and 550° F. after aging 48 hours at 550° F. than the
solution-type formulation, No. 47. An adhesive tape-filler formulation,
No. 57, without maleic anhydride and glycerol was low in strength at elevated
temperatures. A tape-filler formulation, No. 53, of resin E-6 alone without
anhydride or glycerol modification had no strength and fell apart when removed
from the press after a cure of 60 minutes at 400° F. The most promising of
these E-6 formulations, No. 47B, when aged for 100 and 200 hours at 550° F.
and tested, had practically no strength (table 3).
Adhesive formulations of resins E-7 and E-8 (table 7) even with aluminum
and arsenic pentoxide filler were low in strength at 550° F. after heating
for 48 hours at 550° F.
Conclusions
Adhesive formulations of polyamide resins combined with various melaminetype compounds are not considered promising materials for heat-resistant
adhesives for bonding of metal. The polyamide resin was shown to have high
resistance to thermal degradation in bonds of steel, but attempts to develop
cross linkage and strength at elevated temperatures with the melamine components were unsuccessful.
Epoxy resins combined with a vinyl-type copolymer of ethyl acrylate and
maleic anhydride and with the chemical maleic anhydride were found to have
promise as heat-resistant adhesives for stainless steel. Some cross linkage
was presumably formed as joint strengths approaching 200 pounds per square
inch at 550° F. were obtained after joints had aged for 48 hours at 550° F.
Epoxies of the ally' glycidyl ether type of bisphenol A (E-1 and E-3), tetrakis
(hydroxyl phenyl) ethane (E-2), and phenol Novalac resin (E-4) were most
promising.
A significant increase in bond strength at 550° F. was obtained when certain
of the epoxy resin-anhydride formulations containing 100 percent of aluminum
powder (Alcoa 123) and 16 percent of arsenic pentoxide, based on the weight
of resin components, were formed into a tape adhesive of asbestos cloth
28-PO-47 sized with A-1100 silicone resin. Theuse of these inorganic components, aluminum, and arsenic pentoxide, increased the bond strength to
400 pounds per square inch and higher at 550° F. Greater amounts of arsenic
Report No. 1883
-10-
•
•
pentoxide up to 32 percent decreased the strength of bonds tested at 550° F.
after having aged for only 3 hours at 550° F. but caused an increase in
strength in bonds aged for 48 hours at 550° F. Presence of arsenic pentoxide
thus appeared to retard the initial rate of cure but contributed to a higher
degree of cure and cross linkage and greater resistance to thermal degradation
when adhesives were heat aged for longer periods of time. The most promis-'
ing epoxy resins in. these tape-adhesive formulations were the glycidyl ether
types, resins E-1 and E-2. A strength of about 400 pounds per square inch at
550° F. was retained after 200 hours' aging at 550° F. with the formulation
No. 58-1 containing resin E-2, vinyl anhydride copolymer, aluminum, and
arsenic pentoxide impregnated into an asbestos cloth tape.
High strength at 550° F. was obtained also with certain epoxy resins, without
anhydride modification, with the aluminum and arsenic pentoxide filler in the
asbestos tape form. The most promising of these formulations was adhesive
No. 52 with resin E-1, 100 percent of aluminum dust, and 16 percent of
arsenic pentoxide impregnated into asbestos cloth which had a strength of
610 pounds per square inch at 550° F. after aging 200 hours at 550° F.
The rather remarkable results with arsenic pentoxide as a curing agent and
degradation inhibitor for epoxy resins emphasizes the need for further
research on this element and its compounds for use in adhesives for metal.
Similar elements which exhibit properties of both the metals and nonmetals or
are amphoteric, such as antimony, tin, zinc, and aluminum would be of
interest also.
Report No. 1883
-11-
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N I e-ii
SUBJECT LISTS OF PUBLICATIONS ISSUED BY M.
•
FOREST PRODUCTS LABORATORY
The following are obtainable free on request from the Director, Forest Products
Laboratory, Madison 5, Wisconsin:
List of publications on
Box and Crate Construction
and Packaging Data
List of publications on
Chemistry of Wood and
Derived Products
List of publications on
Fungus Defects in Forest
Products and Decay in Trees
List of publications on
Glue, Glued Products
and Veneer
List of publications on
Growth) Structure, and
Identification of Wood
List of publications on
Mechanical Properties and
Structural Uses of Wood
and Wood Products
Partial list of publications
for Architects, Builders,
Engineers, and Retail
Lumbermen
List of publications on
Fire Protection
List of publications on
Logging, Milling, and
Utilization of Timber
Products
List of publications on
Pulp and Paper
List of publications on
Seasoning of Wood
List of publications on
Structural Sandwich, Plastic
Laminates, and Wood-Base
Aircraft Components
List of publications on
Wood Finishing
List of publications on
Wood Preservation
Partial list of publications
for Furniture Manufacturers,
Woodworkers and Teachers of
Woodshop Practice:
Note: Since Forest Products Laboratory publications are so varied in subject.
no single list is issued. Instead a list is made up for each Laboratory
division. Twice, a year, December 31 and June 30 / a list is made up
showing new reports for the previous six months. This is the only item
sent regularly to the Laboratory's mailing list. Anyone who has asked
for and received the proper subject lists and who has had his name placed
on the mailing list can keep up to date on Forest Products Laboratory
publications, Each subject list carries descriptions of all other subject lists.
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