Polymer matrix composite materials with improved mechanical properties with ozone

Abstract

The invention relates to new polymer matrix composite materials developed to increase their resistance to atmospheric conditions and increase their service life by delaying aging. The invention relates to obtaining polymer matrix composite materials that are resistant to atmospheric conditions and have an increased service life, especially by containing fillers in certain proportions to preserve the mechanical properties of the material.

Description

[0001] POLYMER MATRIX COMPOSITE MATERIALS WITH IMPROVED MECHANICAL PROPERTIES WITH OZONE

[0002] Technical Field

[0003] The invention relates to new polymer matrix composite materials developed to increase their resistance to atmospheric conditions and increase their service life by delaying aging.

[0004] The invention particularly relates to obtaining polymer matrix composite materials with increased service life and resistance to atmospheric conditions by reaction with ozone, by comprising fillers in certain proportions to preserve the mechanical properties of the material.

[0005] State of the Art

[0006] Ultraviolet rays, high temperature, humidity and similar atmospheric conditions trigger aging in composites and lead to a decrease in mechanical properties. One of the important factors affecting the properties of polymer-based composite materials under atmospheric conditions is ozone. Ozone affects the properties of many types of polymers. The reaction of ozone with organic and inorganic compounds results in the formation of harmful products such as free radical peroxide, hydroxide or hydroperoxide.

[0007] As a result of research in the literature, it is seen that a decrease in the strength of composite materials exposed to ozone is observed, and as a result the improvement method is not specified and only the results are recorded. In one study, in order to examine the effect of ozone on polymers and polymer-based composites, the composite material was exposed to ozone for 1 to 4 months. The results showed that the addition of filler accelerated ozone-induced degradation, and no innovations were made to improve it. Another study examined the characterization of aging of hybrid composite rods and pure resin in ozone and high temperature. It showed that residual stresses after aging at 1400 for one year were minimal but signif icant at temperatures above 1600. In another study, the aging effects of laminated composites processed with carbon fibers and thermosetting epoxy resin were evaluated when immersed in ozone and water. The results obtained showed that laminated composites tested at room temperature and conditioned only with ozone gave 17% lower tensile strength and 26% lower tensile strength when subjected to water immersion. However, no studies have previously been conducted on the improvement of polymeric composite materials as a result of the reaction with ozone.

[0008] Some studies have been carried out on anti-aging techniques in composite materials. However, these studies do not include ozone aging, they are generally studies on how to improve composite materials under conditions such as exposure to UV rays or moisture. In a study, composite samples were prepared by adding aluminum particles to epoxy resin to improve UV aging properties. The results showed that aluminum particles effectively improved the anti-UV aging properties of epoxy resin. In another study, a polymerization process was applied by grafting renewable cardanol onto carbon fiber surfaces to strengthen the fiber / matrix interface. As a result, it was observed that this additive increased the interlayer sliding strength of the material by approximately 40% and significantly increased its anti-hydrothermal aging properties. In another study, by synthesizing C3N4 on the carbon fiber surface, the interfacial properties of the carbon fiber reinforced epoxy resin composite were improved and an increase in the resistance of the material to hydrothermal aging was observed. In another study, graphene nanoplatelets (GNP) were added to the epoxy matrix to improve the mechanical properties of carbon fiber / epoxy composite materials. The results showed that the GNP volume fraction and distribution had a significant effect on the transverse mechanical properties of the hybrid composite.

[0009] When studies on ozone aging in the present art are examined, it is seen that ozone is used only as a disinfectant and cleaning agent. In addition, it has been observed that atmospheric conditions trigger aging in composites and cause a decrease in mechanical properties, and it has been noticed that there is no study to improve this situation. For this reason, a need has arisen for polymeric composite materials whose mechanical properties are improved as a result of the reaction with ozone in the state of the art.

[0010] As a result, it has become necessary to make a development in the relevant technical field due to the negativities described above and the inadequacy of existing solutions on the subject.

[0011] Purpose of the Invention

[0012] The invention is inspired by current situations and aims to solve the above-mentioned deficiencies. The main purpose of the invention is to obtain polymer matrix composite materials comprise metal oxide powder, thus improves its mechanical properties by reacting with ozone, are resistant to atmospheric conditions, and have an increased service life.

[0013] The purpose of the invention is to produce zinc peroxide and oxygen products as a result of the reaction of zinc oxide, which is an additive added at different rates to plastics and polymeric composite materials aged by exposure to atmospheric conditions, ozone and moisture, with ozone, thus providing an improvement in the mechanical properties of the composite material.

[0014] Another purpose of the invention is to obtain safer and longer-lasting products.

[0015] Another purpose of the invention is to develop a method for obtaining reinforced composites resistant to atmospheric conditions, in which fabrics made of synthetic fibers such as glass, carbon, aramid or natural fibers such as jute, sisal and linen can be used.

[0016] In order to achieve the purposes described above, the invention is a polymer matrix composite material with improved mechanical properties, resistance to atmospheric conditions, increased service life as a result of the reaction with ozone, and comprises fiber reinforced fabric, thermosetting resin, hardener and metal oxide powder.

[0017] In order to achieve purposes described above, the invention is a production method to obtain a polymer matrix composite material that is resistant to atmospheric conditions and has an increased lifetime, and comprises the following process steps: i. Cutting fiber reinforced fabric into specific sizes, ii. Cleaning the mold and applying releasing agent on the mold, iii. Laying the cut fabric on the mold and closing the mold, iv. Preparing the resin mixture with thermosetting resin, hardener and metal oxide powder, v. Impregnation the fabric with resin mixture under vacuum and curing it, vi. Removing the cured fabric from the mold, vii. Exposing the composite product that removed from the mold to ozone.

[0018] The structural and characteristic features and all the advantages of the invention will be understood more clearly by means of the figures given below and the detailed description written with references to these figures, and therefore the evaluation needs to be made by taking these figures and the detailed description into consideration. Figures to Help Understand the Invention

[0019] Figure 1 is a graphical view of the tensile strength of samples without ZnO additive after ozone exposure

[0020] Figure 2 Illustration of the change in tensile strength of the composite material under 300 pphm ozone concentration

[0021] Figure 3 Illustration of the change in tensile strength of the composite material under 500 pphm ozone concentration

[0022] Figure 4 Illustration of the change in tensile strength of the composite material under 700 pphm ozone concentration

[0023] Figure 5 is a SEM image of carbon fiber reinforced composite sample without additives and treatment

[0024] Figure 6 is an image of ZnO added and untreated carbon fiber reinforced composite sample

[0025] Figure 7 is O element elemental analysis images of the composite material with ZnO added and under 300 pphm ozone concentration

[0026] Figure 8 is O element elemental analysis images of the composite material with ZnO added and under 500 pphm ozone concentration

[0027] Figure 9 is O element elemental analysis images of the composite material with ZnO added and under 700 pphm ozone concentration

[0028] Detailed Description of the Invention

[0029] In this detailed description, preferred embodiments of the product and method, which are the subject of the invention are described only for a better understanding of the subject.

[0030] The invention relates to a polymer matrix composite material with improved mechanical properties, resistance to atmospheric conditions, and increased service life, as a result of its reaction with ozone, and a method for obtaining it. Said composite material comprises fiber reinforced fabric, thermosetting resin, hardener and metal oxide powder. Said metal oxide powder is preferably zinc oxide powder. Table 1 gives the preferred and usable amounts by weight of the composite material components of the invention. Table 1 Product recipe of the invention

[0031] The fiber reinforced fabric in the composite material of the invention comprises individuals or combinations selected from carbon, glass, aramid, basalt, linen (flax), hemp, jute and sisal.

[0032] The thermosetting resin contained in the composite material of the invention is selected among epoxy resin, vinyl ester resin and polyester resin.

[0033] Fibers such as carbon, glass, basalt, aramid, linen, hemp, sisal and woven or non-woven surface fabrics made from these fibers serve as reinforcement in composite materials. Such fibrous structures are the main load-carrier elements in composite materials and plastics. Therefore, it provides more load carrying capacity than engineering plastics. Although resins and plastics have a certain strength, their load carrying capacity is limited. For this reason, they are reinforced with such fibrous structures. Essentially, resins and plastics serve as matrix for such fibrous structures and ensure equal and balanced distribution of the load on the material. Depending on the conditions of use, resins and plastics age and their lifetime decreases as they are affected by daylight and other atmospheric conditions. Accordingly, the polymer matrix composite material, which is subject of the invention comprises metal oxide powder preferably zinc oxide. Said metal oxide powder reacts with ozone and as a result of the reaction, zinc peroxide and oxygen products are formed, thus improving the mechanical properties of the composite material and increasing its lifetime.

[0034] In the composite material, which is subject of the invention, thermosetting resins such as epoxy or vinyl ester, polyester (epoxy, vinyl ester, polyester, etc.) and hardener are used as matrix elements. Thermoset is a plastic that hardens when heated and maintains this state forever. Thermoset is one of two basic groups into which polymers are divided according to their thermal behavior. They are more sensitive to mechanical effects and loadings by forming a three-dimensional structure through the cross-links (covalent and interchain) between chain molecules. Their rigidity ensures that their elastic modulus and strength are higher than other polymer types (thermoplastics and elastomers). Elasticplastic deformations, which occur due to the sliding-rotating movements of the chains because of the weakening or breaking of secondary bonds (Van der Waals bonds) at high temperatures, are not seen in thermosets. Because of the rigidity brought by crosslinks instead of Van der Waals bonds, the plastic deformation ability of traditional thermosets is almost non-existent compared to other polymers, that is, they are brittle. Their brittleness is, in a sense, one of the reasons why their fracture toughness is relatively low. They maintain their mechanical properties at high temperatures and have high thermal stability. However, they do not melt or show viscous behavior. If there is an increase in temperature that could deform the cross-links, they will start to burn directly. Their recycling is not possible due to these features. When the tensile curves are examined, it is seen that they break when they immediately pass the yield point as a result of homogeneous elastic deformation. This is evidence indicating how low their plastic deformation capabilities are. Thermosetting polymers can only be shaped during polymerization and maturation. Thermosetting resins form a strong cross-linked structure after completing the polymerization and maturation processes, and their resistance to heat and corrosion is higher than thermoplastic materials.

[0035] In a preferred example of the product, which is subject of the invention, zinc oxide is used as the metal oxide. Zinc oxide (ZnO) powder is odorless and has the appearance of a white powder with a bitter taste. It has the ability to absorb carbon dioxide and ultraviolet rays in the atmosphere. While it can be dissolved in acids and alkalis, it is insoluble in water and alcohol. Although Zinc Oxide is a non-toxic substance, it is highly flammable. In our invention, zinc oxide is preferred because it is an oxygen-containing compound. The object here is to ensure its reaction with ozone and to improve the mechanical properties of the composite material as a result of the reaction.

[0036] The subject of the invention is a production method to obtain a polymer matrix composite material that is resistant to atmospheric conditions and has an increased lifetime, comprising the following process steps: i. Cutting fiber reinforced fabric into specific sizes, ii. Cleaning the mold and applying releasing agent on the mold, iii. Laying the cut fabric on the mold and closing the mold, iv. Preparing the resin mixture with thermosetting resin, hardener and metal oxide powder, v. Impregnation the fabric with the resin mixture under vacuum and curing it, vi. Removing the cured fabric from the mold, vii. Improvement of the mechanical properties of the material by exposing the composite product that removed from the mold to ozone

[0037] In the process step i.) of the method, which is subject of the invention, the fabric comprising individuals or combinations selected from carbon, glass, aramid, basalt, linen, hemp, jute and sisal is cut in certain sizes.

[0038] In the process step iii) of the method of the invention, the resin mixture is prepared by mixing hardener and metal oxide powder and thermoset resin selected from epoxy, vinyl ester and polyester. The metal oxide powder mentioned herein is preferably zinc oxide powder.

[0039] In the method of the invention, the composite material removed from the mold in the process step vii) improves its mechanical properties by subjecting it to ozone in the ozone chamber, preferably at ozone concentrations of 300 pphm or 500 pphm or 700 pphm for 168 hours.

[0040] The mentioned resin mixture is prepared with the formula "(fabric weight*surface area*number of fabric layers)+1 OOOgr".

[0041] In a preferred embodiment of the method, which is subject of the invention, Carbon fiber fabric is cut in 6 layers in 50*50 cm dimensions. A flat glass plate is cleaned so that no dust or dirt remains on the mold, and a mold releasing agent is applied on the cleaned mold. Then, carbon fiber fabrics are laid on top of each other in the same direction on this mold. Peel ply, which is the fabric that provides surface roughness, is laid over the entire mold and fixed with adhesive. Mesh fabric is laid on it to ensure easy flow of the resin mixture through the channel. Infusion paste adheres so that it surrounds the mould. The resin mixture is prepared with thermosetting resin, hardener and metal oxide powder. Vacuum tanks are connected to the lines, the vacuum bag is cut according to the mold and holes are opened for the hose inlets required for infusion. The vacuum bag is glued with paste so that there is no air leakage. Ports that will allow the passage of the resin mixture are connected to the mechanism. The hoses are connected to the ports, the flow of the resin mixture is started to impregnate the fabrics under vacuum and the process continues until every part of the mold is wetted with resin, then it is kept under vacuum until it cures. After curing, the bag is removed from the mold and the product is removed from the mold. Finally, ozone treatment is applied to the product removed from the mold to improve the mechanical properties of the material.

[0042] Experimental studies and analyzes were carried out to determine the properties of the composite material, which is the subject of the invention. For the standard, an additive- free and untreated sample was obtained. For the product sample, which is subject of the invention, the following detailed steps were applied;

[0043] A. Cutting fibrous material or fabric into specific sizes,

[0044] B. Cleaning the mold to be used in production so that there is no dust or dirt on it,

[0045] C. Applying mold releasing agent on the cleaned mold,

[0046] D. Laying fibrous materials or fabrics on top of each other in the desired directions,

[0047] E. Closing the mold

[0048] F. Connecting the ports that will allow the passage of thermoset resin (epoxy, vinyl ester, polyester, etc.) to the mechanism,

[0049] G. Turning on the vacuum pump and checking whether there is leak or not,

[0050] H. Preparation of the required amount of thermosetting resin mixture,

[0051] I. Connecting the hoses to the ports and starting the resin flow and continuing the process until every point of the mold is wetted with resin,

[0052] J. Keeping the part under vacuum until cured,

[0053] K. After curing, removing the bag from the mold and removing the part from the mold,

[0054] L. Cutting of samples by wet cutting in accordance with test standards

[0055] M. Keeping some samples in the ozone chamber at specified ozone concentrations (300 pphm, 500 pphm, 700 pphm) at 23°C, 40% and 80% humidity for 168 hours, in accordance with the prepared experimental plan,

[0056] N. Taking the samples from the ozone chamber after 168 hours and preparing them in accordance with the tensile test standards,

[0057] O. Applying tensile tests to the samples and recording the results,

[0058] P. Taking samples from the sections obtained as a result of the test, examining under an electron scanning microscope and taking their images,

[0059] Q. Applying elemental analysis to samples and recording the results. While the tensile strength value was 494.1 MPa in the additive-free and untreated sample, this value decreased by 32.7%, 25% and 17.5%, respectively, when the additive was added at different rates. In addition, the tensile strength values of samples which are exposed to ozone and without additives showed a decrease compared to the initial value. These values are 34.02%, 25.82% and 31.14% lower than the tensile strength values of the additive-free and untreated sample given above, respectively. When these two external factors (metal oxide contribution and ozonation) are considered together, it has been observed that they have a different effect on the strength of the material. Additionally, all processed samples were compared among themselves. Under 300 pphm ozone concentration, the tensile strength value of the additive-free sample was measured as 329.0225 MPa. It was observed that with the addition of ZnO as an additive at different concentrations, this situation was in the opposite direction to the untreated group. The tensile strength values of samples containing 1 , 2 and 4% ZnO increased by 2.26%, 10.62% and 20.08%, respectively. The change in tensile strength was also calculated for the samples under 500 and 700 pphm ozone. For 40% humidity, the percentage changes of samples below 500 pphm ozone increased by 1.75%, 21.75% and 27.75%, respectively. In samples under 700 pphm ozone, unlike other conditions, an 8.14% decrease in tensile strength was observed between the additive-free sample and the 1% added sample. It was observed that there was an increase in other contribution rates. The increase in tensile strength for samples with 2% and 4% additives is 12.65% and 16.4%.

[0060] Metal oxide, preferably zinc oxide, which is an additive added to the composite by adding it to the resin, plays an important role in reducing the strength of the composite material. This can be seen from the tensile test results we applied to carbon fiber-epoxy composite material samples obtained with zinc oxide. In addition, the tensile strength values of additive-free pure samples exposed to ozone showed a decrease compared to the initial value. When we look at these values, they are 34.02%, 25.82% and 31 .14% lower than the tensile strength value of the reference sample, respectively. Table 2 shows the wt% O ratios and stress values of the samples.

[0061] Table 2 %wt O ratios and stress values of the samples

[0062] In Figure 2-4, it is given a graphical view of the change in tensile strength of the composite material at ozone concentration of 300 pphm, 500 pphm and 700 pphm, respectively. In Figure 5 and Figure 6, SEM images of carbon fiber reinforced metal oxide-free and untreated composite samples and ZnO-added untreated samples are given.

Claims

CLAIMS1. The invention is a polymer matrix composite material with improved mechanical properties, resistance to atmospheric conditions and increased service life, as a result of the reaction with ozone, characterized by comprising; ber reinforced fabric, thermosetting resin, hardener and metal oxide powder.

2. The composite material according to claim 1 , characterized in that; the said fiber reinforced fabric comprises individuals or combinations selected from carbon, glass, aramid, basalt, linen, hemp, jute and sisal.

3. The composite material according to claim 1 , characterized in that; the said thermosetting resin is selected from epoxy resin, vinyl ester resin and polyester resin.

4. The composite material according to claim 1 , characterized in that; metal oxide powder is zinc oxide powder.

5. The invention is a production method to obtain a polymer matrix composite material that is resistant to atmospheric conditions and has an increased service life, characterized by comprising; the following the process steps: i. Cutting fiber reinforced fabric into specific sizes, ii. Cleaning the mold and applying releasing agent on the mold, iii. Laying the cut fabric on the mold and closing the mold, iv. Preparing resin mixture with thermosetting resin, hardener and metal oxide powder, v. Impregnation the fabric with the resin mixture under vacuum and curing it, vi. Removing the cured fabric from the mold, vii. Exposing the composite product that removed from the mold to ozone.

6. The method according to claim 5, characterized in that; in the process step i), the fabric comprising individuals or combinations selected from carbon, glass, aramid, basalt, linen, hemp, jute, sisal, is cut into specific sizes.

7. The method according to claim 5, characterized in that; in the process step iii), the resin mixture is prepared by mixing hardener , metal oxide powder and thermoset resin selected from epoxy, vinyl ester and polyester.

8. The method according to claim 5 or 7, characterized in that; the said metal oxide powder of the process step iii) is zinc oxide powder.

9. The method according to claim 5, characterized in that; in the process step vii), the composite product is exposed to ozone in the ozone chamber at ozone concentrations of 300 pphm or 500 pphm or 700 pphm.

10. The method according to claim 9, characterized in that; the ozonation process is applied for 168 hours.

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