J / CERTAIN PROPERTIES CF PAPREG AS AEFECTED BY LAMINATING PRESSURE, RESIN CONTENT, AND VOLATILE CONTENT Revised Cctcbcr 1943 i iO^i This Report is One of a Series Issued In Cooperation with the ARMT-NAVT-CIVIL COMMITTEE on AIRCRAFT RESIGN CRITERIA Under the Supervision off the AERONAUTICAL IOARR No. 1394 UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE FOREST PRODUCTS LABORATORY Madison, Wisconsin In Cooperation with the University of Wisconsin iHmtiuL i ^— ^ Ul i. i I Ltj iv.ty''" Digitized by the Internet Archive in 2013 http://archive.org/details/propertieOOfore £^ F L^I1 JI?'-! E3 ! ' [ '"' ? r P/ - FR ^ G AS A F PECTE P BY LA '■' IN AT IV G iSSTJRE, RESIN CO V i, USD VOLATI! E CONTfiNTi By R. J. SEIDL, Assistant Chemical Engineer G. E. JACKIN, Associate Industrial Specialist F. K. BAIRD, Senior Chemist Preliminary experiments, previously reported by the Forest Products Laboratory.'! indicated that certain trends exist between laminating pressure, resin content, and volatile content of resin- impregnated paper and some of the properties of papreg.i Results of a more thorough investigation of these variables are presented in this report. TEST MATERIAI The base paper (N. R. 2037) used in these experiments was made on the Forest Products Laboratory experimental paper machine from a commercial Mitscherlich spruce sulfite pulp especially developed from Laboratory specifications for this purpose. The significant physical properties of this paper are: Ream weight (25x40-500) pounds 31.0 Thickness mils 2 .5 Porosity (G-urley) seconds 9 Density grams per cc. 0.69 Tensile, in machine direction pounds per square inch 11,900 —This mimeograph is one of a series of progress reports prepared by the Forest Products Laboratory to further the Nation's war effort. Results here reported are preliminary and may be revised as addi- tional data becoae available. —"Effect of Laminating Pressure on Certain Properties of High-strength Paper Plastic," Mimeograph Mo, 1394, March 1943. (Restricted) "high-strength Laminated Paper Plastics for Aircraft," Mimeograph Mo, 1395, revised April 1943 (Restricted) 3 "The name "papreg," identifying the experimental high-strength laminated paper plastic developed by the Forest Products Laboratory has been sent to the U, S. Patent Office ^or registration, Mimeo, No, 1394 (Revised) -1- Tensile, adr ; - tie Lreotion —pounds per re inch 4, / - Tensile, aver" ^ pounds per The base paper was impregnated with b apir it-soluble p ! Lie ■ lin (Bakelite '-"' 3526). In this report the tern "resin content" ra to the difference in weightj between an area of the air-dry - per and /equal area of the paper immediately as it e ar :es frc impregnator drying tunnel, expressed as a percent •. >d- er weight. The volatile content as used in this report refers to difference in weight between a resin-treated sheet immediately is it emerges from the impregnator drying tunnel and its weight after drying in ar oven at 160° C. for 10 minutes, bhe weight differ* being expressed in percent of the -first '• weight.* Therefore, I volatile oontent of a resin-treated paper is included in bl 9 resin non- tent determination. For a given content of resin solids a ol volatile content also causes a change in the resin content. In making the resin-treated paper the conditions of cr the impregnator (fig. 1) were established by test for three resit cc - r s, each of which included about 4.0 percent volatile c -•■ Thr?se may be considered the basic combinations of resin sol and volatile natter. The rate of resin application, t - resin bath, speed of travel of the paper, and the air velocity erature in the drying tunnel, were establi for the basic o ' ins. Increases in volatile content were t >de by Lng air temperature in the drying tunnel holding all other conditions constant as possible. After impregnation, sheets of the treated paper were out from the roll, issembled for mo] ling, i sealed in moisturepronf paper bo minimize changes in v caused by contact with the air. All panel", were parallel laminated at : ". for 12 removed fr^m the press while they were I . 3ures used varied from 25 to 2000 pounds ier inch. in contents of the treated papers rare 27.5, '. , and 3'". t. For convenience in discussion, however, these will hereafter be r« to as 27, 35 and 40 percent, respec ; . eont 3 run with three volatile contents r from 3.9 to 4.1, 5.8 to 5.4, and 7,1 to 7,3 percent. Hereafter these will he ref rrec to as 4, . , and 7 percent, r stively. The diJ ces bet the actual and referred- values are within the experimental error, and insofar as riasi ic tiea are concerned, are insl t, is necessary to differentiate between this volatile oontent &1 volatile content produced by absorption of moisture during oondition- ■ of impregnated paper. It Is recognised r Ln-tr papers having the same volatile oontent by test, but prod ; the o 4 s, may yield • •• • are considerably - t, . . (94 (Revised) - - The same number of sheets were used for all panels. Before molding, the weight of each paper assembly was recorded. After remove. 1 from the press each panel including the flash (extruded resin) was weighed. The flash was then removed and each panel was again weighed to determine the resin lost as flash. Because of difficulties in entirely removing the flash without also removing some of the paper, these weights can be considered only as approximations. It was recog- nized that the percentage of flash i ,r as dependent upon the dimensions of the panel. This determination was made on panels of about 10- by 10- inch dimensions. Test specimens were prepared and conditioned, specific gravity was determined, and specimens were tested for tension, compression, bending, and. water absorption, according, to procedures set forth in "Proposed Federal Specification for Organic Plastics; General Specifi- cation (Methods of Physical Tests)" July 7, 1942, DISCUSSION OF RESULTS Since resin content, volatile content, and molding pressure are interdependent variables, they are considered simultaneously in the dis- cussion of their effect upon properties of papreg* The data not only show the effect, of each variable, but also indicate the relationship that exists between them. Erratic results were sometimes obtained, especially at the extreme limits of the ranges because of loss in vola- tile content during melding at the lowest pressure and because of excessive extrusion of resin in the high range of pressures. Erratic results at the extro le limits cf the ranges indicate that for this base paper and resin the practical limits of resin content, volatile content, and laminating pressure had been reached. The properties of papreg, as affected by rosin content, volatile content, and laminating pressure, are shown by the data recorded in the tables. Interpretation of this data and the discussion of individual properties is from the graphs wherein the numerical values of such, properties are plotted against laminating pressures. Because the effect of resin content shows more range than do the effects of volatile content, the effect, of resin content is shown by a comparison between families of curves of the same series while the effect of volatile content is shown by a comparison between the curves of the same family. Although considerable scatter is sometimes shown, by the test values, especially these for laminating pressures below 250 pounds per square inch, the smoothed curves are a visual average of the test values. Pue to the scatter of the plotted test values at the three volatile contents for any resin content, the relative positions of the curves, at laminating pressures below 250 pounds per square inch, are not particularly significant in the graphs of strength properties. The families of curves for water absorption and specific gravity show, in general, a more significant relation between the volatile contents for a given resin content. Mimeo. No. 1394 (Revised) -3- Ultimate Tensile "' r^ngth The ultimate tensile str of papreg increased to a maxi- and then remained nearly constant as the laminating pressure was increased. This was true for each condition of resin content i volatile content studied. The data are given in table 1 an figures 3, and 4. Using paper with 27 percent resin content and 4 percent vc~ - tile content the ultimate tensile strength was increased from 33,000 to nearly 45,000 pounds per square inch when the laminating presr.ure increased from 50 to 500 pounds per square inch. The maximum tensile strength was not appreciably increased at higher molding pressures (: : . 2) . Using paper with volatile content of 4 percent end resin content of 35 percent, the tensile strength increased from 34,000 to 42,30° pounds per square inch and at 4 percent volatile content and 40 percent resin content it increased from 30,300 to 39,900 pounds per square inch c- the same range of pressure (figs. 3 and 4). Although the same trei exhibited at all resin contents the tensile strength decreased with an increased resin and volatile content. The data also show th low range of laminating pressure higher tensile strength was obtained by using higher resin content. When using paper with ' ' percent resin con- tent, nearly 500 pounds per square inch laminating pressure was required to produce papreg with the maximum strength but at 35 percent resin con- tent the maximum value was re ched at about 250 pounds per square inch • ressure. The rate of increase of tensile strength with increased laminating pressure was greater when 35 percent resin content was used than when 27 percent was used. The effects of changes in volatile content on the ultimate tensile strength of papreg were of smaller magnitude than those caused by changes in resin content. Ultimate Edgewise Compressive Strength. The resin content of the treated paper has a highly imp- - effect on the edgewise compressive strength of the molded plastic as shown by the data of table 2 and figures 5, 6, and 7, The ultimate compressive strength increased as the resin content was increased. Papreg molded with 5.5 percent volatile content at 250 pounds per square inch reached an edgewise compression value of 20,000 pounds per squr - inch v ' percent resin content was used, but the use of 40 percent resin content under comparable conditions increased the compressive str- bo 24,100 pounds per square inch. Although the tensile strength decreased with an increase in resin t when the pressures were greater than about 2 r.ds r square inch, the compressive strength was, in general, increased w: an incr in resin content throughout the entire range of laminating :re covered, . . 4 (Revised) -4- For nearly all combinations of volatile and resin contents the ultimate edgewise compressive strength increased to a maximum and then remained nearly constant as the laminating pressure was increased (figs. 5, 6 and 7). For each combination of volatile and resin contents the maximum compressive strength was reached at less than 500 pounds per square inch molding pressure. When a resin content of 27 percent was used a laminating pressure of nearly 500 pounds per square inch was necessary to produce the maximum compressive strength. At the higher resin contents it i .vas possible to develop the maximum compressive strength at a molding pressure as low as 200 pounds per square inch. Changes in volatile content were found to affect the compressive properties of papreg to a lesser degree than changes in resin, content. For a resin content of 55 percent, slightly higher compressive strength resulted when using 4 percent volatile content as compared with values obtained when using 7 percent volatile content* For instance, at 4- per- cent volatile content and a molding pressure of 250 pounds per square inch, the compressive strength was 23,000 pounds per square inch wheroas at 7 percent volatile content the corre spend ing value we s 21,500 pounds per square inch. At each resin content the general trend was toward lower compressive strength with increased, volatile content. Modulus of Rupture The modulus of rupture., like the ultimate tensile and compressive strengths, increased, to a maximum and remained nearly constant as the laminating pressure was increased for each condition of resin and vola- tile content used. The acta are given in table 3 and shown graphically in figures 8, 9, end 10. Paper treated with 27 percent resin required a molding pressure of about 500 pounds per square inch to produce papreg with the maximum bending strength for that resin content. When the resin content was increased to 35 percent, the maximum strength was reached at about 250 pounds per square inch molding pressure. When a resin content of 40 percent was used the maximum modulus of rupture occurred at about 200 pounds per square inch molding pressure. The highest value of these maxima, however, occurred at the lowest resin content. If the molding pressure is above 250 pounds per square inch an advantage is to be gained in the modulus of rupture if a low resin content is used but if molding is done at a lower pressure the advantage is gained by usin? a high resin content. For example, at 27 percent resin content, 5.5 nercert volatile content and 1000 pounds ner square inch molding pressure a modulus of rupture of 41,300 pounds per square inch resulted. A comparable panel using 40 peroent resin content produced a value of 38,20^ pounds per square inch indicating a gain of 8.1 percent by the use of the lower resin content. However, at 75 pounds per square inch molding pressure and the same volatile content, the modulus of rupture of the panel made -'hen using 27 percent res^n content was 31,540 Mimeo. Np, 13S4 (Revised) -5- pounds per square inch and when using 40 percent resin content the modulus of rup 4 is 7)3,500 pounds per square inch indicating a gain percent by use of the higher resin content, 'At all resin contents the change in maximum modulus of rupture due to a change in volatile content from 4 to 7 percent was less tl 5 percent. With laminating pressures above 300 pounds per square inch the effect of volatile content on the modulus of rupture seemed to be pronounced at lower resin content but at the lower molding pressur s the effect was more pronounced at the highest resin content. ".'.'oduli of E las ticity in Tension , Compression, and Bending The moduli of elasticity in tension, compression, and bending increased to a maximum and then remained substantially constant as the laminating pressure was increased for each condition of resin and vola- tile content used. The data are given in table 4 and the relal ips are shewn in figures 11 to 19 inclusive. The highest moduli were pro- duced by papreg molded at a resin content of 27 percent. Increasing the resin content up to 40 percent caused some loss in these strength values. Increasing the r^sin content from 27 percent to 40 percent c of ahou 4 : 10 percent in the maximum moduli of elasticity in tension and compression and a loss of approximately 12 percent in the b modulus. The discussion of the data on ultimate tensile str and modulus of ruptui . indicated that, in the range of lew laminating pressure, the use of high resin content sometimes yielded hi I r V than those produced by low resin content, whereas, at laminating pressures greater than 250 pounds per square inch the maximum values were obtained by the use of the lowest resin content. With the moduli of elasticity, however, the lowest resin content produced the highest moduli values over the entire range of laminating pressure used. A laminating pressure from 400 to 500 pounds per square inch was required to approach the maximum moduli for a resin content of 27 percent. At a resin content of 35 percent, a laminating pressure from 250 to S00 pounds per square inch was necessary to develop the maximum, and at 40 •cent resin content only about 200 pounds per square inch mold] pressure was required to produce the maximum strength* The effect of the various volatile contents for all of the resin contents on tl moduli of elasticity in tension, compression, a bend- ing did not appear to bo significant and though trends may be noted so small that they easily coul^ be caused by normal variations in rial or test procedures. . "94 (Revised) Specific Gravity The specific gravity of papreg, as shown in table 5 and figures 20, 21, and 22, increased to a maximum and then remained approximately constant as the Irminating pressure was increased. At 40 percent resin content a maximum specific gravity of about 1.40 was reached at 200 pounds per square inch laminating pressure and at 55 percent resin con- tent a maximum of about 1.41 was reached at 250 pounds per square inch laminating pressure. When 27 percent resin content was used a maximum of 1.42 was approached at 500 pounds per square inch molding pressure and a trend observed toward slightly higher values by an increase in molding pressure up to 2000 pounds per square inch. It is, therefore, evident that the lowest resin content produces the highest specific gravity. This is probably because the fiber component of papreg has a greater density than the resin has. The rate of increase of specific gravity with an increase in lami- nating pressure up to 500 pounds per square inch was greater as the resin content was increased. Although a fairly high specific gravity (about 1.35) can be obtained with 27 percent resin content at about 250 pounds per square inch molding pressure it ie necessary to use 500' or mere pounds per square inch in order to obtain a specific gravity above 1,40. The effect of volatile content on specific gravity was more pro- nounced in papreg made at the low resin content than at the higher resin contents. At 200 pounds per square inch molding pressure and 27 percent resin content the specific gravity* was" 1.23, 1.31 or 1.34 for vola- tile contents of 4, 5.5, o>- 7 percent, respectively. However, at the sane molding pressure and 40 percent resin content the specific gravity was 1.40 for each of the volatile contents. Water Absorption Data obtained from water absorption tests on papreg are given in table 6. Papreg made with 2 7 percent resin content and volatile contents of 4, 5,5 and 7 percent showed a greo.t decrease in water absorption as the molding pressure was increased from 25 pounds per square inch to 250 pounds per square inch (fig, 23), For example, when using a volatile content of 4 percent and 25 pounds per square inch molding pressure, the water absorption was 21.3 percent but this was reduced to 6.1 percent by the use of 250 pounds per square inch molding pressure. Higher molding pressures up to 1000 pounds per square inch caused only a comparatively slight further reduction to 5 percent, Within the range of laminating pressure used, increased volatile content caused reduction in the water absorption. This is exemplified by the values obtained with a resin content of 27 percent at 250 pounds per square inch laminating pressure, where the water absorption values Mimeo. No. 1394 (Revised) -7- were 6.1, 5.2 and U.3 percent for volatile contents of U, 5.5 and 7 percent, respectively. The use of relatively high volatile content and low resin content permitted the vise of lower laminating pressure to obtain papregs having equivalent water absorptions. For example, 500 pounds per square inch laminating pressure was required to produce papreg having a water absorption of 5«2 percent when using 27 percent resin con- tent and U percent volatile content, whereas when the volatile content was increased to 5»5 percent the same water absorption was obtained at 250 pounds per square inch, and at 7 percent volatile content only about 125 pounds per square inch was necessary. At all resin contents the effect of volatile content on water absorption was diminished with the use of higher laminating pressures (figs. 23, 2U and 25). '-Tien 27 per- cent and 35 percent resin contents were used the highest values of water absorption were associated with the lowest volatile content, but when Uo percent resin content was used the variation in water absorption caused by change in volatile content was not significant. A considerable decrease in the water absorption of papreg was obtained when the resin content was increased from 27 to 35 percent, and a further but less significant decrease followed an increase in resin content to Ho percent. At 35 percent resin content with 5«5 to 7 percent volatile content a minimum water absorption of about 3 percent was ob- tained at a molding pressure of 200 pounds per square inch. At 25 pounds per square inch laminating pressure the water absorption obtained at 27 percent resin content and 5*5 percent volatile content was about twice that obtained when 35 percent resin content and the same volatile content was used. The lowest water absorption resulted from the use of ho percent resin content, and a comparatively lo\^ water absorption obtained for this resin content throughout the entire range of laminating pressures used. Values under U.O percent were obtained at 25 pounds per square inch laminating pressure and were not greatly changed by additional pressure up to 2000 pounds per square inch. On the other hand a resin content of 27 percent is insufficient to produce papreg having the best water resistance, regardless of volatile content cr laminating pressure. In practically every combination of resin content and volatile content used, the water absorption was slightly increased with increased laminating pressure after a certain pressure had been exceeded. This apparent point of reversal occurred at approximately 500 pounds per square inch molding pressure when 27 percent resin content was used, at about 200 pounds per square inch with 35 percent resin content, and at 150 to 200 pounds per square inch with ^0 percent resin content. As the volatile content was increased for a given resin content, the trend of the effect was to move this minimum point in the direction of lover laminating pressure. This revertal in water absorption is explained* by the tendency for resin to be extruded during molding when the higher ranges of resin content, volatile content, and laminating pressure were used. Approximate values for resin losses as flash are given in table 6. Ilimeo. No. 139U (Revised) -g_ These data show that over 11,5 percent of the weight of a molded panel was lost as flash when 40 percent r r sin content, 7 percent volatile content, and 1000 pounds per square inch molding pressure was used. For this extreme condition the total amount of resin lost was about 25 percent of the total resin applied to the paper. At the opposite extreme of resin and volatile contents, namely 27 percent resin content, 4 per- cent volatile content, and 1000 pounds per square in«h molding pressure, the percent of the weight of the molded panel lost as flash was only 0.8 percent or approximately 3 percent of the total resin applied to the sheet. Conclusions The following general conclusions were drawn from the data obtained under the conditions described. 1. The ultimate tensile strength and modulus of rupture of papreg increased to a maximum and remained virtually constant as the laminating pressure was increased for all resin and volatile contents. The maximum was reached at lower molding pressures as the resin content was increased. The highest tensile strengths were obtained with the 1 wrest resin content and the lowest volatile content. 2. The edgewise compressive strength of papreg increased to a maximum and then remained constant as the laminating pressure was increased for all resin and volatile contents. The compressive strength was increased as the resin content was increased and the highest values were obtained with the lowest volatile content. 3. The moduli of elasticity, in tension, compression and bend- ing, increased to a maximum and then remained substantially constant as the laminating pressure was increased for all resin and volatile con- tents. The maximums were reached at lower molding pressures as the resin content was increased. The highest values were obtained at the lowest resin content. No significant trends because of changes in vole- tile content were evident. 4. The specific gravity of papreg increased to a maximum and remained nearly constant as the laminating pressure was increased for all resin and volatile contents. The maximum specific gravity was reached at lower laminating pressures as the resin content was increased. No appreciable effect on this property was observed by changes in vola- tile content at 40 percent resin content. 5. The water absorption of papreg decreased as the resin content was increased. In fact, resin content was £he most important factor in reducing the water absorption. This was especially noticeable in the low range of laminating pressure. Increasing laminating pressure appreci' ably affected this property only at the lowest resin content. The water absorption was decreased with increased volatile content only in the low range of resin content. Mimeo. Wo. 1394 (Revised) -9- O O A C3 D U a B r-t •H m »a 'J d B o •J 5 LP. 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eo «-i f- r— vjo vjd vjO »x» r— as.*-* K>rAt\J rO c\j c\j c\j aj cu c\j rAfA r*"\ kn k-> i*y«o \jO o O ^D --* OOOMMONtOMNN rA K\ K>> K> (VI t\j OJ CU C\j C\j rj C\j -* o -» t— o o o r— j- C\J J- O H MrtHHNW oj c\j_* ^o bo I i-t SO VjO C\J Jt f\ rH K-»VjO 10 .3- k\0 no O-* r— O <-• f— o> ooooooooo rH r4 (\J rHVjO j-^r cjho er> o> r— o <-* CO lO^f j- j- j- j- ^KU M -* r- i r— r— r— t— r-t dtnoud ood 1 O o O O eO60vjDj* r«-\ C\j vo O iricov^j iA_*^t-* -*.*.* J* lf\ oooooooddoHN r-« r*-\ c\j vo 6o r— ao r«-\t\jr»-cr»o f«-\ r-l CO Vj3 UT\ UfMfMfN lf>^f _* l("\ 4- 60 rt oooooooooc5drH K\OM KVjD H lf\C^H WO uTl >4 a CD .rl jo er iQino^QiAooooo iirSr--oc\Jir\r-oi?SQOO HHHHWNj\OP as o^~ •H 00 *£ a oo a> id 6 Eh Ofl o fl -< O 09 a K 111 O Tt a t a> u o u ft. CD CO p, a o ^ ■h a) *> t. es o cp CD O I CD U O CD -H a! co 3 ft a Gb ^5 cvi u r-l O H . *J> fe a) o • -rt LT> a (8 01 T( ^1 CD CO * (-, aj CD a t) i-l CD %* r-t Tl CD -1 CD CD O r-t a, r-< O t. £ a! = p. o • 4» h -4 >» O xl ^c •e b a a *» a) ^» rJ ^ re 1. — The Forest Products Laboratory resin >r and dryer, for preparing laminating paper. 46,000 Is 44fl00 40.000 36.000 32,000 Z8.000 n • 200 300 400 500 (,00 700 800 LAMINATING PRE55URE ( POUNDS PER SQUARE INCH) 900 1000 Figure 5.— ltutmua-.dgewi.e-coapree.lon teluea of papreg It thr.. Yolatlle content Tela., end at a re.ln content of 2? percent. u — LEGEND- RE5IN CONTENT- 35 PERCENT D VOLATILE CONTENT-40 PERCENT A VOLATILE CONTENT- 5 5 PERCENT O VOLA TILE CONTENT- 70 PERCENT 100 ZOO 300 400 500 600 700 BOO LAMINATING PRESSURE (POUNDS PER SQUARE INCH) 900 1000 Figure 6. — llajtlmun-edgewlae-oompreealon Tsluea of papreg at three Tolarlle zz~'.'-r.: emlaei and at > - content of 35 percent. kj kl K 5 1 8 18,000 24,000 20,000 16,000 LEGEND RESIN CONTENT- 4-0 PERCENT □ VOLATILE CONTENT- 4.0 PERCENT A VOLATILE CONTENT'S. 5 PERCENT — VOLATILE CONTENT -7.0 PERCENT 100 200 300 400 500 600 700 800 LAMINATING PRESSURE {POUNDS PER SQUARE INCH) 900 z Figure 7.--Bexla»i»-edgewiee-compr»ealon TmJuea of papreg at three eoletlle content reluea and at a re.ln content of Uo percent. 1000 44,000 40.000 36,000 32,000 26,000 14,000 100 200 300 400 500 bOO TOO 800 900 LAMINATING PRESSURE. (POUNDS PER 5QUARE INCH ) Figure &. — Modulus of rupture of papreg at three volatile oontent values and at a resin content of 27 percent. 1000 44,000 ^s 40,000 §1 36,000 32,000 X^ £• 28,000 24,000 LEGEND: RESIN CONTENT- 35 PERCENT D VOLATILE. CONTENT- 4.0 PERCENT & VOLATILE CONTENT- S. 5 PERCENT O VOLATILE CONTENT- JO PERCENT 100 200 300 400 500 600 700 800 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) 900 1000 Figure 9>*-Modulus of rupture of papreg at three volatile oontent values and at a resin content of 35 percent. 40fi00 3bP00 32,000 28,000 0r- L EG END ■■ RESIN CONTENT-40 PERCENT Q VOLATILE CONTENT-4.0 PERCENT A VOLATILE CONTENTS. 5 PERCENT O— VOLATILE CONTENT-7.0 PERCENT 100 200 300 400 500 600 700 600 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) 900 WOO ZM 50576 F Figure 10. — Modulus of rupture of papreg at three volatile content values and at a resin content of U0 peroent. -- I i i 4,000,000 J.bOOjOOO 3?00,000 2. BO OP 00 2+0OP0O 4,0 OOP 00 aoopoo 3,2oop 00 2600.000 2400000 LEGEND FESlN CONTENT- Z7 PERCENT D VOLATILE. CONTLNT-4 PERCENT L\ VOLATILE CONTENT- 5 5 PERCENT O VOLATILE CONTENT- 70 PERCENT 200 300 400 500 600 700 600 LAMINATING PRESSURE (POUNDS PER SQUARL INCH) 900 1000 Flguro 11.— Bodulut of ol«.tlolty lo tomlon of p«pr. e «t thr.o Tol.tilo contont t»:u«s icc «t * mla contont of 27 porcor.t. 100 200 300 400 500 bOO 700 800 LAMINATING PRESSURE ( POUNDS PER SOUARL /A/CN) 900 1000 Fl £ ur« 12.— Uodulua of eUitlelty In ton»!on of p«prog •-. throo roUtll. oontont mluoi «j.c «-. • ro.ln oontont of 35 porcont. 4,000.000 3,b00. 3.200. 000 ZfiOOjpOO 2400.000 _ ' D LEGEND: RESIN CONTENT -40 PERCENT O VOLATILE CONTEXT- 4:0 PERCENT A VOLATILE CONTENT- 5.5 PERCENT O VOLATILE CONTENT- 70 PERCENT ZOO 300 400 500 600 700 600 LAMINATING PRESSURE (POUND5 PER SQUARE INCH) 300 1000 ri*ur» 1?.— Nadului or - tonilon of papror. ot thro* nlitlli oontont nluti and »t * roiln oontont of UO poroont. 1 s o in ft; ! s 3.600,000 3,100000 2JB0O,000 2400.000 LEGEND' RESIN CONTENT- 27 PERCENT □ VOLATILE CONTENT-40 PERCENT A VOLATILE CONTENT- 5.5 PERCENT O VOLATILE CONTENT-TO PERCENT 100 200 300 400 500 600 700 800 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) 300 1000 Figure \k. — Modulus of elasticity in compression of papreg at three volatile content values and at a resin content of 27 percent. Ct- Or a- <0 3,600,000 3,100,000 I 2,800,0 00 2,400.000 2,000,000 m LEGEND ■ RESIN CONTENT- 35 PERCENT U VOLATILE CONTENT- 4.0 PERCENT A VOLATILE CONTENT- 5.5 PERCENT O VOLATILE CONTENT- 7.0 PERCENT '± 100 200 300 400 500 600 700 600 900 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) Figure 15. — Modulus of elasticity in compression of papreg at three volatile content values and at a resin content of 35 percent. 1000 x ,i ^ ^ < o 3,200.000 2,800,000 24 00,000 2,000,000 =^ f LEGEND RESIN CONTENT- 40 PERCENT D VOLATILE CONTENT- 40 PERCENT A-r — VOLATILE CONTENT- 5.5 PERCENT O VOLATILE CONTENT- 1.0 PERCENT 100 £00 300 400 500 600 700 800 LAMINATING PRES5URE (POUNDS PER SQUARE INCH) 900 Z M 50578 r Figure 16. — Modulus of elasticity in compression of papreg at three volatile content values and at a resin content of ^0 percent. 4,000.000 <0 X SI I 3.600.000 3.200,000 2J300.000 2.4J0.000 ZflO 0,000 ■ 4—-U--- LEGEND RESIN CONTENT- 21 PERCENT D VOLATILE CONTENT- 4-0 PERCENT L\ VOLATILE CONTENT- 5 5 PERCENT O VOLATILE CONTENT- 70 PERCENT I I I I ^ 100 ZOO 300 400 500 600 700 600 LAM/NAT NG PRE SURE (POUNDS PER SQUARE INCH) 900 1000 Figure 17. -Modulus of elastic. ty in ben ing of pmpre^ st three Toletlie content relies mad et e resin content of ( " pe cent. 1' 3f.00fi00 3.2.00000 2,800,000 2400,000 2,000.000 ^ LEGEND' RESIN CONTENT- 35 PERCENT D VOLATILE CONTENT- 4-0 PERCENT A VOLATILE CONTENT- 5 5 PERCENT — VOLATILE CONTENT- 70 PERCENT 100 200 300 400 500 600 700 800 900 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) Figure 18 --Modulus of slastlclty ;n banding of pepreg st tnrss Tolstlle contact rsi-es end st s rssln content of 35 psr.sr.t. 1000 5 UOOfiOO I \6 00.000 t£ 1.400.000 — 4=---- — sssss BBS . — — — ■ _ _ __ ~=2 Qi T F LEGCND- RESIN CONTENT- 4-0 PERCENT A D VOLATILE A VOlATILL VOLATILL 1 . Luniti : COlNTE, : CCNTE, 1 1-«W re NT- 5.5 PL NT- 70 PL ITCENI :rcent r JfCENT 100 200 300 400 500 600 700 800 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) 900 1000 ■j79 r Figure 19. — Modulus of elasticity In bending of peprer st three volatile content Tmlues end at e resin content of 40 percent. LEGEND ■ RESIN CONTENT- Z7 PERCENT U VOLAT/LL CONTENT-40 PERCENT A VOLATILE CONTENT- 5.5 PERCENT O VOLATILE CONTENT- 7.0 PERCENT ZOO 300 400 500 600 700 800 LAMINATING PRE55URE (POUNDS PER 5QUARL INCH) 900 1000 Figure 20. — Speoifio gravity of papreg at three volatile oontent values and at a resin content of 27 percent. 200 300 440 500 600 700 800 900 LAM/NATING PRESSURE (POUNDS PER SQUARE INCH) Figure 21. — Specific gravity of papreg it three volatile oontent values and at a resin oontent of 35 percent. 1000 100 ZOO 300 400 500 600 700 800 LAM/NATING PRESSURE (POUNDS PER SQUARE INCh) 900 Z M SO SAfi T Figure 22. --Specif io gravity of papreg at three volatile content values and at a resin content of **0 percent. fOOO u 20 18 t M B I 10 1 1 \ 1 1 1 1 \ \\ \ LEGEND- RESIN CONTENT- Z7 PERCENT D VOLATILE. CONTENT-4-0 PERCENT A VOLATILE. CONTENTS 5 PERCENT O VOLATILE. CONTENT-TO PERCENT \ ° ) I K'+L o^J >-. 0_. z. 100 ZOO 300 4G0 500 bOO 700 600 900 LAMINATING PRESSURE (POUNDS PEP SQUARE INCH) 1000 Fl(ur« 23.— l«t«r tbaorptlos of p*prt( tt thr«« rol»-.:.» oontvot r»lu parent* «ad »*. • ratla content of ? 7 ZOO 300 ■fOO 500 600 700 600 LAM/NAT/NG PRESSURE (POUND5 PER SQUARE INCH) rifur* ?**.--»otor oboorptloo of poproi ot throo Tolotll* ooatoet mlMl oai o? • roola ooeeoK of « porooat. /*W 1 LEGEND resin content- 4-0 percent □ volatile: content ^hj perxznt a volatile content- 5 3 percent o volatile content- 70percent \ n 1 v 100 ZOO 300 400 500 bOO 700 000 900 LAMINATING PRESSURE (POUNDS PER SQUARE INCH) 1000 ■ M oboorptles of poprog ol throo volotllo oooloot !*!«•■ on* porooot . roou oentjoat of *. 'HIVfcKbll r CM 3 1262 08866 5897