Reactions of phenols with tung oil

As regards the aromatic ring substitution reactions of various kinds of phenols with tung oil under acidic conditions, an investigation was made on the influences of the kinds and substitution positions of alkyl groups of the phenlos on the reaction. Alkyl phenols increased in reactivity in the order of ortho, meta, and para in the position of alkyl substitution. This can be attributed to the preferential para addition of tung oil to the phenol nucleus as reported in the previous paper. The larger alkyl group gave increased reactivities in the reactions of alkyl phenols with tung oil. This has something to do with compatibilities between phenols and tung oil (differences in solubility parameter between phenols and tung oil).     

Reaction of 3-methyl phenol with tung oil

The aromatic ring substitution reaction of 3-methyl phenol with tung oil under acidic conditions was carried out. The product was analyzed to find out if 3-methyl phenol was subjected to the ring substitution reaction with tung oil at its conjugated double bonds. Up to two molecules of 3-methyl phenol were addition-reacted with the conjugated triene of one eleostearyl group of triglyceride of α-eleostearic acid which is the major component of tung oil. The 4-position of 3-methyl phenol was preferentially subjected to the cresol's ring substitution. Therefore, up to 6 mol of 3-methyl phenol was added to 1 mol of tung oil, most of which was bonded to 3-methyl phenol at its 4-position. When 3-methyl phenol was reacted with a relatively large amount of tung oil, the substitution reaction occurred at the 6-as well as 4-position of 3-methyl phenol to yield a tung oil dimer having 3-methyl phenol units in its molecule. The above results were confirmed by infrared (IR), nuclear magnetic resonance (NMR), and high-speed liquid chromatographic (HLC) analyses.     

Preparation of pressure-sensitive adhesives from tung oil via Diels-Alder reaction

In this study, tung oil was polymerized with a dimaleimide (4,4’-methylene-bis(N-phenylmaleimide) (MPMI) and two diacrylates (poly(propylene glycol) diacrylate (PPGDA) and bisphenol A glycerolate diacrylate (BPAGDA) via Diels-Alder reaction (DA reaction) to prepare pressure-sensitive adhesives (PSAs). On the one hand, the polymer of tung oil and MPMI was readily prepared however it was too rigid to serve as a PSA. On the other hand, the polymerization of tung oil with PPGDA or BPAGDA resulted in PSAs with peel strengths ranging from 0.1 to 0.2 N cm⁻¹ and loop tacks ranging from 0.4 to 0.5 N. Nevertheless, tung oil reacted readily with acrylic acid to form adducts (TOAA) with lower content of conjugated diene groups than those of tung oil. The use of TOAAs instead of tung oil to polymerize PPGDA failed to increase the peel strength of the resulting PSAs. However, polymerizations of TOAAs with BPAGDA resulted in PSAs with much higher peel strengths and much higher loop tacks than the polymerization of tung oil with BPAGDA. In addition, the introduction of a small amount of MPMI in the polymerization of TOAA and PPGDA significantly shortened the curing time.     

桐油及其衍生物的改性在高分子材料中的应用进展

综述了4种桐油改性方法并且介绍了桐油及其改性衍生物在高分子材料应用中的主要进展.讨论了桐油的Diels-Alder反应、Friedel-Crafts反应、氧化聚合和烯烃自由基聚合改性反应及聚合机理,在此基础上,对桐油的改性方法及其在高分子材料中的应用前景进行了展望.     

Synthesis of UV-curable tung oil and UV-curable tung oil based alkyd

Two UV-curable tung oil-based resins were synthesized via a Diels–Alder cycloaddition. An UV-curable tung oil (UVTO) was prepared from bodied tung oil and trimethylolpropane trimethacrylate (TMPTMA). An inhibitor, phenothiazine, was added to avoid homopolymerization of TMPTMA. The UV-curable tung oil alkyd (UVTA) was prepared from the monoglyceride process and then reacted with TMPTMA via the Diels–Alder reaction similar to the UVTO. The UVTO and UVTA were characterized by ¹H NMR, ¹³C NMR, and MALDI-TOF mass spectroscopy. The UVTO and UVTA were formulated with a free radical reactive diluent, tripropylene glycol diacrylate (TPGDA) and photoinitiator Irgacure 2100. Photo differential scanning calorimeter (Photo-DSC) was used to investigate curing kinetics of the UVTO and the UVTA. Both the UVTO and UVTA were photocurable with the UVTA formula exhibiting a faster curing speed than the UVTO.     

Studies in the expression of oil from tung fruit

Summary 1. Tests indicated that best results in yield of crude and filtered oil by an expression procedure are obtained with a tung meal containing 4.2% moisture and 20% shell. 2. The drying of tung meal using an initial air temperature of 320° F. appeared to adversely affect the yield of filtered oil from the expeller process. 3. A filtration test was developed for determining the amount of foots in a crude tung oil. 4. It was found difficult to obtain efficient oil expression from tung meals containing filter cake; in one test with this material the resulting press cake was high in oil content, while in another test the crude tung oil contained about twice as much foots material as was present in crude tung oil from tung meal containing no filter cake. 5. The expression of tung oil from a tung meal consisting of ground old tung kernels and tung shell was found difficult if not impossible. This difficulty appeared to be due, at least partly, to the fact that the meal from old kernels will not plasticize when subjected to heat and pressure. When these kernels were mixed with new kernels no difficulty was experienced in expressing the tung oil from the meal. 6. Tests indicated that hulling the moist tung fruit in the grove does not interfere with the expression of the oil if the moist dehulled tung fruits are properly dried before pressing. 7. A process was developed for producing a clear tung oil by treating the crude oil with a chemical agent to precipitate certain non-oil constituents in the crude tung oil followed by either pressure filtration or centrifugation. 8. When tung oil filter cake was mixed with an equal amount of tung press cake, over 98 percent of the oil could be solvent-extracted by petroleum solvents. Presented at the American Oil Chemists’ Society meeting, New Orleans, La., May 10–12, 1944. Some of the material was presented at the American Tung Oil Association meeting. Pensacola, Fla., April 28–29, 1944, and published in the proceedings. Agricultural Chemical Research Division Contribution No. 145.     

A monoglyceride-rich tung oil product

A method for preparing tung monoglycerides (1) by the reaction of tung oil with an excess of glycerol in the presence of sodium methoxide as the catalyst has been adapted to the preparation of large batches of material. Laboratory scale studies have shown that a product analyzing as containing up to 50% of tung monoglycerides is produced when the reaction is carried out at 150°C. for one hour with an excess of 1 mole of glycerol and 1% of sodium methoxide (based on oil weight). The data were applied successfully to three batchwise pilotplant preparations using from 30 to 47 pounds of tung oil to produce a product containing from 32% to 45% tung monoglycerides. Unreated glycerol was successfully separated from the product by centrifugation, with no water or salt solution washing, to give a product containing 1.5% to 3.5% free glycerol. Difficulties were encountered in analyzing the product for monoglyceride, and it was found that the triene conjugation contributed to high results, However, there also appear to be components other than simple monoglycerides in the product which analyze as monoglycerides to give a falsely high value, as evidenced by differences found by analyses of the products before and after essentially complete hydrogenation.     

桐油的超临界二氧化碳萃取及溶解度研究

采用超临界二氧化碳(SC-CO_2)萃取技术对从桐籽中提取桐油的工艺进行了研究,考察了物料粒径、萃取温度、萃取压力等对桐油提取率的影响并得到适宜的操作条件.结果表明.优化条件下桐油提取率达到55.16%,桐油回收率达到91%.还利用SC-CO_2萃取桐油的实验数据求得了桐油在SC-CO_2中的溶解度,并用Chrastil方程对溶解度数据进行关联.在30～50℃和25～55 MPa条件下,桐油在SC-CO_2中的溶解度为0.004～0.026 g/L.Chrastil方程关联的平均相对误差为8.41%.     

Untersuchungen des Reaktionsverlaufes und der Produkte der säurekatalysierten Reaktion von Phenolen mit Holzöl, 2. Vergleichende untersuchungen an verschiedenen phenolen

In this paper the acid-catalysed reaction between phenols and tung oil is investigated for 4 different phenols (phenol, o-, m- and p-cresol). This reaction is important for the production of modified resins for electrical insulating laminates. In particular by means of ¹³C-NMR- and IR-method it is proved that phenols are C-alkylated by tung oil in the manner of a Friedel-Crafts-reaction exceptionally. The reaction positions at the phenols are determined. Further, the rates of the reaction of phenol with the eleostearic acid esters are compared for the four different phenols.     

Materials balance in a tung oil mill

Summary Weights were determined and analyses made of tung fruit milled and of all products leaving the mill for two runs of about 90 tons each in a commercial mill under normal operating conditions. Dry matter, oil, and nitrogen in the fruit were satisfactorily accounted for in products leaving the mill, 101% of the oil being accounted for in each run. This showed that the methods of analysis and sampling were accurate. Losses occurred principally in particles of kernels occluded with the hulls and in the screw-press cake. Seventy-eight and 82% of the oil in the fruit was recovered as filtered oil. Repressing the filter-press cake by adding it back to the stream of ground nuts just before they entered the screw-presses was not proven to be economical as at the end of the run just as much cake was on hand, and it had as high an oil content as if no filter cake had been fed back through the screw presses. Only about half as much oil could be filtered per filtration cycle, resulting in an increase in cost of labor and a decrease in filtering capacity. The apparent oil content of the screw-press cake decreases by about 2% after four to eight days as compared to its apparent oil content at the time of pressing because of polymerization. Thus, screw-press cake samples should be analyzed for oil as soon as possible after extrusion. Both of these laboratories are maintained by the Agricultural Research Service of the U. S. Department of Agriculture.     

Preparation and some properties of tung oil monoglycerides

Summary Several methods for the preparation of tung oil monoglycerides were investigated. Products richest in both monoglyceride (78%) and triene conjugation (63% as eleostearic acid) were obtained by glycerolysis with sodium methoxide in pyridine solution. Attempts to increase the content of monoglyceride and triene conjugation by selective solvents were unsuccessful. The monoglycerides were effective in lowering the surface tension of water as well as the interfacial tension of several oils, including tung oil, against water. The tung oil monoglycerides behaved as fugitive emulsifiers and, after drying, retarded the removal of spray residue (lead arsenate) by washing with a water spray more than did other emulsifiers, such as cottonseed oil monoglycerides. The ammonium soap of tung oil fatty acids also acted as a fugitive emulsifier. Both of these laboratories are maintained by the Agricultural Research Service of the U. S. Department of Agricuture.     

桐油制备生物柴油的工艺研究

以四川桐油为原料,研究了生产生物柴油过程中的酯交换反应条件的影响。结果表明,当甲醇和油脂的物质的量之比超过6∶1后,桐油转化率提高范围很小。当油脂中含有少量游离脂肪酸和水分时,通过甘油虽可测定油脂的转化率,但是后处理时乳化严重,甲酯的损失较大从而影响甲酯的收率。反应温度对反应的转化率影响较大。通过测定桐油生物柴油的物性,表明桐油生物柴油的低温流动性良好,可以作为低温流动性改进剂与其它油脂制备的生物柴油混合使用。闪点为194℃,硫含量为70.75μg/g。     

桐油改性双环戊二烯不饱和树脂的合成研究

利用缩聚反应后期桐油与双环戊二烯不饱和聚酯(DCPD-UPR)主链上不饱和双键的Diels-Alder(D-A)反应合成了桐油改性DCPD-UPR,研究了各种原料用量对桐油改性DCPD-UPR其浇注体力学性能的影响。结果表明:当顺酐与苯酐的物质的量比为2∶1～3∶1,双环戊二烯与顺酐物质的量比为0.6～0.8∶1,1,2-丙二醇与二甘醇物质的量比2∶1,缩聚反应后期加入10%(质量分数)桐油,苯乙烯质量分数为35%～40%时,获得的桐油改性DCPD-UPR粘度适中,浇注体的断裂伸长率提高了78.2%,冲击强度提高了82.0%。     

Preparation and properties of glycerin ester of tung oil modified rosin

Tung oil modified rosins (TR) were prepared by reaction rosin with different amount of tung oil via Diels‐Alder addition reaction and further used in the formulation of glycerin ester of tung oil modified rosins (GTR) with flexible characteristics. The effects of the amount of tung oil on the bromine value, molecular weight, thermostability, physical, and tackifying properties of GTRs were studied. The results showed that the bromine value of GTRs decreased and molecular weight of GTRs increased with the increase in the amount of tung oil. Meanwhile, increasing the amount of tung oil resulted in a significant decrease in both the softening points and viscosities of GTRs, but a slight increase in the thermostability of GTRs due to the incorporation of the flexible fatty chains into the rigid hydrophenanthrene units in rosins. Applied in PU adhesive as tackifier, the increase of the flexible chains content in GTRs led to an increase first and then decrease in both the miscibility of GTRs with PU and the T‐peel strength of adhesives. The elongation at break of films increased monotonously, but their tensile strengths increased first and then decreased with increasing the flexible chains content in GTRs. GTRs with desired properties were prepared when the tung oil/rosin weight ratios were in the range from10/100 to 40/100. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1700–1706, 2013     

Stability and film properties of tung oil modified soybean alkyd emulsion

A series of tung oil modified soybean alkyd emulsions are prepared by an inversion emulsified technique. In these alkyd resins, the tung oil contents are about 0, 12.5, and 25.0 wt % (based on the total oil). Using IGEPAL CO‐630 as the surfactant, a very stable alkyd emulsion can be obtained. With the increase of the tung oil contents in alkyd emulsions, the initial droplet sizes of the emulsions increase dramatically. Aging under 50°C can eliminate the difference in droplet sizes; the final droplet sizes of the emulsions are about 50 nm. The alkyd resins also have good hydrolytic stability. The tung oil contents in the alkyd resins also strongly influences the film properties; suitable tung oil content improves the film gloss. An atomic force microscopy investigation shows that the film from the alkyd emulsion is more water sensitive; after a 50‐h deionized water immersion, the film surface appears to have a lot of dents. This indicates that the film surface may be very rich in surfactant species. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1698–1706, 2000     

The performance of biodegradable tung oil coatings

Using immersion tests, viscosity measurements, FTIR and SEM, as well as biodegradation tests, biodegradable tung oil coatings were investigated. Results showed that the curing times for different formulae decreased as the amount of catalyst increased. During the curing process, there was an initial induction period where the viscosity remained more or less the same, and after a certain time, a sharp increase in viscosity was observed. The steady viscosity increased with time, revealing a continuous autoxidation process. Microorganisms in the soil attacked the surfaces of the tung oil films either uniformly on the whole plate or at specific weak points, leading to decreased volume, blurring of the small humps as well as holes. The weak point on the crosslinked chain was located at the carbonyl-containing groups, where chemical biodegradation occurred more easily and faster.     

Thermosetting polymers from cationic copolymerization of tung oil: Synthesis and characterization

The cationic copolymerization of tung oil with the divinylbenzene comonomer initiated by boron trifluoride diethyl etherate produces promising plastics. The gel times are largely dependent on the relative composition and the reaction conditions and vary from a few seconds to 1 h. Controlled reactions producing homogeneous materials can be obtained by (1) lowering the reaction temperature or (2) decreasing the initiator concentration to less than 1 wt % or (3) adding a certain amount of a less reactive oil, such as soybean oil, low saturation soybean oil (LoSatSoy), or conjugated LoSatSoy to the reaction. The resulting polymers are rigid and dark brown in color. The weight % of the starting materials converted to the crosslinked polymer is ∼85–98% as determined by Soxhlet extraction with methylene chloride. The structure of the bulk product is that of a crosslinked polymer network plasticized by a small amount of low molecular weight oil. The chemical composition of the bulk polymers varies with the original composition of the tung oil system. Dynamic mechanical analysis shows that the resulting products are typical thermosetting polymers with densely crosslinked structures. The modulus of the plastics is approximately 2.0 × 10⁹ Pa at room temperature. One broad glass transition is observed at approximately 100°C. Thermogravimetric analysis shows that the tung oil polymers are thermally stable below 200°C with a 10% weight loss in air around 430°C. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1044–1056, 2000     

Studies on the refractive index and dispersion of American tung oil

1. Tung oil has a refractive index and a dispersion so far above those of any other common oil that both are valuable criteria for identification purposes. With proper equipment the dispersion, in addition to the refractive index, can be determined with little extra effort and would confirm the conclusions drawn from the refractive index.
2. Mixtures of tung oil with another vegetable oil (except oiticica and other rare conjugated oils) can be analyzed to within 0.5% from the refractive index for either the sodium or the mercury line if the refractive indices of the separate oils are known. The mixtures can be analyzed from the dispersion to within about 1% of the correct composition if the dispersions of the separate oils are known. If the adulterating oil is not known the adulteration can be more closely estimated from the depression of the dispersion than from the depression of the refractive index.
3. When tung oil is bodied by heat the refractive indices for the sodium and mercury lines and the dispersion fall rapidly and continuously to the point of gelation, but the changes are so similar that no worth-while additional information is obtained by determining more than one refractive index. The fact that refractive index decreases as viscosity increases suggests the use of the refractive index in controlling the bodying of tung oil.
4. Other things being equal, the refractive index for the mercury line should give more accurate information on tung oil than that for the sodium line because of the greater changes in the refractive index for the mercury line upon adulteration or heating.
5. A correlation coefficient of 0.83 was found for refractive index with the diene number of tung oil. A lower correlation coefficient was found for refractive index with the iodine number, but the latter would probably be higher if a more accurate method for the determination of the iodine number of tung oil were available.

     

Renewable thermoset copolymers from tung oil and natural terpenes

The cationic copolymerization of tung oil, limonene, and myrcene as comonomers, initiated by boron trifluoride, is presented and discussed in this work. Dynamic mechanical analysis revealed that all copolymers behave as thermosets. FTIR spectra for both copolymers, after extraction with dichloromethane, suggested that the major component of the insoluble fraction was reacted tung oil (a cross‐linked triglyceride network). Likewise, unreacted tung oil was found to be the main component of the soluble phase. Also, all the copolymers showed only one tan δ peak, indicating no phase separation. Glass transition temperature (Tg) increased with the myrcene content and decreased almost linearly as the limonene content increased. Furthermore, the Fox and Loshaek model showed a relatively good prediction of the Tg values of the polymers. The Young's modulus ranged from 33.8 to 4.7 MPa for all tested thermosets. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41155.     

A further study on the composition of American tung oil with special reference to the linoleic acid content

The complete separation of elaeostearic acid from linoleic acid by the irradiation and crystallization of tung oil fatty acids was found difficult if not impossible. The application of several cold alkaline permanganate oxidation procedures to samples of tung oil fatty acids indicated the presence of less than one per cent of linoleic acid in tung oil. A study of the reaction of maleic anhydride with alpha elaeostearic, beta elaeostearic acid, and with the alpha elaeostearic acid glyceride present in tung oil showed that this reagent does not react with them quantitatively but only to 86.6 per cent of the theoretical amount. It was found that the elaeostearic acid content of a tung oil can be calculated by dividing its diene value by 78.4, the determined diene value of pure alpha elaeostearic acid. In this way it was calculated that two samples of American tung oil contained 85.5 and 89.4 per cent of elaeostearic acid. It was found that alpha elaeostearic acid and the mixed fatty acids from tung oil when exposed to the air quickly underwent a change to form an extremely sticky material whose use as an adhesive for insecticides will probably soon be determined.