Analysis Adhesive Strength of Epoxy DGEBA on The Wooden Boat Hull

Epoxy is a thermosetting material that is widely used as an adhesive. Epoxy has the advantages of good tensile strength, bending strength, and thermal stability. Epoxy is an adhesive that can bind various materials such as steel, copper, wood, iron, cement, plastic, and composites. Epoxy can be cured at room temperature with the addition of a hardener (curing agent). The curing agent affects the strength, hardness, durability, and adhesion strength of the epoxy. Along with the advancement of shipping technology, other alternatives were found in the construction of wooden ships, namely the laminate system. Wood lamination usually uses an epoxy resin material. Research on the strength of laminated materials for wooden hulls is an interesting scientific discussion to obtain new alternative materials that can be applied to wooden hulls. With this lamination method, it is very possible to replace wood because, with lamination, the material in addition to having better strength is also easy to obtain at a cheaper price than wood. Considering that this laminate material is still rarely used on ships, it is necessary to test the adhesive material. This research was conducted to see the mechanical characteristics and evaluate the use of laminated materials. The tests carried out included tensile test, and adhesive test which were carried out in the laboratory to obtain results to analyse the strength and durability of the wooden hull. The adhesive strength of DGEBA epoxy on teak wood has the highest adhesive strength on Epoxy-Amide with a paint coating of 4.43 MPa and tensile strength of 1.5 MPa. Meanwhile, the highest adhesive strength for Epoxy-Amine with paint coating is 4.76 MPa and tensile strength of 3.63 MPa which is applied to teak wood as a wooden ship hull material.


Introduction
Technology Epoxy is widely used as a coating material or coating (for example in the automotive sector, piping, etc.), wrapping electronic equipment, replacement for casting on aircraft and automatic machines.Composite materials are also used in the aerospace industry, PCB (Printed Circuit Board), and pressure pipes.In the construction field, it is often used in the manufacture of floors and repair of aircraft lines [1].
1 imahluluk@ppns.ac.idDr. Pierre Castan from Switzerland who succeeded in synthesizing the first epoxy in 1936 years.Dr. S.O.Greenle from America improved the quality of epoxy by inventing an epoxy formula derived from epichlorohydrin and bisphenol A. Epoxy can be called Glycidyl group which has an oxygen chain as shown in Figure 1.1.
Figure 1.1 Epoxy Carbon Chain [2] Epoxy resins are generally produced by reacting epichlorohydrin with bisphenol A in the form of a viscous liquid in a thermoset state.Different resins are formed by varying the proportions of epichlorohydrin and bisphenol A. The resins prepared in this way consist of a mixture of various molecular weights.Figure 1.2 shows the process of epoxy formation.The following are some of the characteristics of epoxy: 1.The bond strength is very good and can bond with almost all materials.2. Having good physical and chemical properties along with varieties of curing, extenders, solvents and fillers that must be formulated properly for different applications.3. It is thermosetting, which when mixed will change from liquid to solid and cannot be melted again [4].
Epoxy resins have unique properties, because they can combine one or more catalysts and curing agents and can function as fillers or fillers to form adhesives.The curing agent is often considered the most important part of the system, reacting with the epoxy resin to change from a liquid state to a hard thermoset state.Examples of several types of curing agents are amines, amides, acid anhydrides, imidazoles, phenols, mercaptans, and metal oxides.Amines are often combined with epoxy resins.
Poly (amino amide) is a condensed polymer.Starting from the non-equilibrium reaction of a number of moles of p-carboranedicarboxylic acid with aromatic tetraamines.This reaction will produce a new property of the polymer.Adhesives are materials used to hold at least two surfaces together firmly and permanently.The properties that must be possessed by an adhesive material are that it must be able to wet the entire surface, be able to adhere to the surface, and be able to withstand loads when a force is applied.The raw materials for adhesives are usually made of polymers, both natural and synthetic polymers [5].

Methodology
Research is a series of scientific activities in the context of problem solving.The function of research is to dilute explanations and answers to problems and provide alternatives for possibilities that can be used to solve problems.The flow chart diagram of this research includes several stages.This research uses several tools and materials.The materials used include DGEBA Epoxy, poly (amino amide), and cycloaliphatic amine.The tools used include specimen prints, digital scales, and aluminum foil.This study uses several tests, including Tensile test (Tensile) where this test is carried out to determine the mechanical properties of the material, the tensile strength refers to ASTM D 638 M and the Adhesive test which is carried out to determine the adhesion or adhesion strength of each coating result, namely wood paint and epoxy using standard ASTM D4541.The flow chart diagram of the study is shown as follows:

Results and Discussion
The epoxy used in this study was Diglycidyl Ether Bisphenol A (DGEBA).Epoxy was prepared by reacting with two different types of hardeners, namely epoxy reacted with poly (amino amide) or (PAA) and epoxy reacted with cycloaliphatic-amine or (AC) as a hardener based on the ratio by weight.Epoxy was mixed in a ratio of 2: 1% by weight of hardener poly (amino amide) and by weight of hardener cycloaliphatic amine.Epoxy-Amine preparation was carried out using the solution mixing method.The preparation was carried out in an aluminum container.The DGEBA and PAA epoxies were stirred continuously, the resulting mixed solution was in the form of a thick and yellow liquid, then the solution was rubbed with a brush on the repaired teak wood using rubbing paper.The solution was cured at room temperature 33 °C for 24 hours.
Meanwhile, the preparation of the Epoxy-Amide was also carried out using the solution mixing method.The preparation was carried out in an aluminum container.The epoxy and cycloaliphatic amine were stirred continuously, the resulting mixture was a thick and transparent liquid, then the solution is applied with a brush on the teak wood that has been repaired using rubbing paper.The solution was cured at room temperature 33 °C for 24 hours.The results showed that there were differences in the results for each different composition.The main difference in epoxy is in the physical condition, namely the epoxy with amine curing agent in the form of solid and not hollow, while the epoxy with amide curing agent in the form of solid, brittle and bubbling.

Adhesive Test Results
This test was carried out to determine the adhesive strength in this study carried out with the ASTM D4541 standard which was applied to teak wood.ASTM D4541 is a test standard where the adhesive strength is expressed in terms of shear strength in MPa.
The research parameters and the choice of curing agent had better compatibility with DGEBA resin as an adhesive material, compared to previous studies shown in table 1.1.This, as was done by Liliana Neagu in 1998, means that the choice of a suitable curing agent can improve the properties of the epoxy better than modifying the resin [6].The test results are shown in Figure 1.6 below, the graph shows that the highest adhesive strength is found in the Epoxy-Amine Adhesive Test specimen with Coating Paint with a large adhesive strength of 4.76 MPa, for the Epoxy-Amide Adhesive Test specimen with Coating Paint the strength is the adhesive is 4.43 Mpa.The lowest adhesive strength was in Epoxy -Amide specimens (Comparison 2: 1) without paint coating with a strength of 3.9 MPa.

Tensile Test Results
Tests to determine the adhesive tensile strength in this study were carried out with ASTM standards applied to teak wood.This adhesive tensile test produces adhesive strength which is expressed in tensile strength in MPa units.The adhesive tensile test specimen is shown in Figure 1.7 below.The results of the adhesive tensile test showed that there was a significant difference in the tensile strength of each specimen.The tensile strength of the specimens for Epoxy-Amine is quite high in the range of 3.63 MPa to 3,01 MPa and the Epoxy-Amide is in the lower range of 1.The results of the tensile strength showed a decreasing trend if no paint was added after the epoxy and hardener coating process.The decrease in tensile strength is caused by the more cavities or bubbling contained in the specimen [7].This can be seen in the graph of the results of the adhesive tensile test in Figure 1.8 below.
For the Epoxy-Amine application on teak with wood paint coating, the highest strength is 3.63 Mpa, while for Epoxy-Amide the highest strength is 1.5 Mpa for Epoxy-Amide application on teak with wood paint coating.The more crosslinking bonds that occur, the longer the chemical structure of the material and the energy required to break the bonds, so that the strength of the material is higher.This is evidenced by the adhesive bond of the epoxy -amine which is more complex than that of the epoxy-amide so that its strength is higher.The tensile strength of Epoxy-Amine is higher than that of Epoxy-Amide because of its longer chemical structure, this is in accordance with the FTIR results of the two adhesive compositions.Based on the results of the tests in this study which consisted of three tests, FTIR, adhesive test and Tensile Test, the results showed that the adhesive or adhesive substance when applied to teak wood for the hull of the ship was more resistant and stronger when added coated or laminated with wood paint.

Conclusion
Based on the research that has been carried out, it can be concluded that: 1. Characteristics of Epoxy-PAA and Epoxy-AC Cured Specimens.The results showed that there were differences in the results for each different composition.The main difference in epoxy is in the physical condition, namely the epoxy with amine curing agent in the form of solid and not hollow, while the epoxy with amide curing agent in the form of solid, brittle and bubbling.2. Effect of hardener amide on the adhesive strength of epoxy DGEBA on teak wood has the highest adhesive strength on Epoxy-Amine with a paint coating of 4.76 MPa and a tensile strength of 3.63MPa.

Figure 1 .
3 shows the chemical structure of poly (amino amide).The form of epoxy bonding of DGEBA with poly (amino amide) is shown in Figure 1.3.The characteristic of this

Figure 1 . 6
Figure 1.6 Graph of Epoxy-Amine and Epoxy-Amide Adhesive Pull Out Test Results

Figure 1 . 8
Figure 1.8 Graph of Epoxy-Amine and Epoxy-Amide Adhesive Tensile Test Results

Table 1 . 2
5 MPa to 1,31 MPa.The results of the adhesive tensile test are shown in table 1.2 below.Epoxy-Amine and Epoxy-Amide Tensile Adhesive Test Results