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Destruction Mechanism Of Epoxy Resin Products (automotive Materials, Flame Retardant Materials)

Aug 03, 2020

1. Epoxy adhesive with high corrosion resistance and electrophoretic coating for car shell primer


The primer of the car shell is generally coated with electrodeposition technology (ED), and epoxy-based adhesives play an important role in this technology. Recently, automobile manufacturing companies have become more concerned about the anti-corrosion requirements of ED adhesives used for phosphate-treated steel surfaces and untreated steel surfaces. Traditional dry fatty acid modified epoxy-based adhesives cannot meet the above requirements. The research on the influence of the salt-spray resistance of a typical thin paint (thickness 25m) on the surface of bare steel found: ⑴The residual hydroxyl in the cured paint (0.2~0.4 equivalent [Note]/100g) The content is very high, which greatly improves the quality of the paint ([Note]: Original: 200~400millieqivalents); ⑵Epoxy-based cationic adhesive is basically oil-free, trimellitic anhydride (TMA) modified hydroxyl-rich ring Oxygen esters and monoepoxy esters with fluidity [Note] (aflow-promotingmonoepoxyesters; CarduraE10), which have excellent salt spray resistance to non-pretreated steels, thus promoting its development. The principle of "high content of hydroxyl" is also reflected in anionic epoxy resin adhesives, and its application has won the favor of various industries in varying degrees. ([Note]: The resin contains a flow promoter-translator's note.)

  

2. Nano polyaniline/bisphenol F epoxy resin system-flame retardant, conductive nano polymer


Both nano-fibril polyaniline (PANI) and nano-sphere PANI have been successfully used to strengthen epoxy resin (EP). The introduction of nano-PANI can reduce the heat release rate of EP and increase its residual carbon content. In the liquid suspension nano-PANI/EP sample, when the amount of nanosphere PANI (weight ratio, the same below) is 1.0%, and the nanotube PANI is 1.0% and 3%, the viscosity of EP can be reduced. The viscosity of EP increases with the increase of the amount of nanospheres and nanotubes PANI. When the dielectric loss tangent (tan) peaks, the glass transition temperature Tg appears in the system. The critical amount of nano-PANI with Tg and modulus is different: nanotube PANI is 1.0%; nanosphere PANI is 5.0%. With the aid of the dynamic mechanical properties and conductivity of the cured product, the percolation threshold of the PANI nanostructure can be identified. Because the aspect ratio of nanotube PANI is the largest, the percolation threshold appears when the dosage is 3%; while the PANI nanosphere does not appear until 5.0%. Nanotube PANI has better electrical conductivity. When the dosage is the same, the volume resistance of the EP/nanotube PANI system is lower than that of the EP/nanosphere PANI system-this may be related to the contact resistance and the percolation threshold. The results of the tensile test show that the tensile strength of the EP substrate is higher when the amount of nano-PANI is lower (for example: 1%). Compared with pure EP, the elastic modulus and toughness [Note] of all nano-EP composite samples are improved. ([Note]: "Toughness improvement" is about the in-depth study of the fracture surface.) It is observed that as the amount of nano-PANI increases, the real permittivity of the material also increases. The increased dielectric constant can be analyzed with the aid of interface polarization.


3. For halogen-free, fire-resistant novel spiral ring phosphorus nitrogen compound/epoxy resin system


A novel, halogen-free, fire-resistant EP system with a vertical spiral and cyclic triphosphor nitrogen base has been designed, and the chemical structure, composition and final product of the spiral ring triphosphor nitrogen precursor have been confirmed. Three curing agents (4,4-diamino-diphenyl (methane), 4,4-diamino-diphenyl sulfone and resole)/EP system were synthesized by a three-step synthesis route. Its Tg>150℃, high semi-coke yield and excellent heat resistance. The flame retardancy test methods include: ①Limiting oxygen index (LOI) test method; ②UL-94V-O vertical combustion test method; ③Chemical analysis of the residual carbon collected from ②. The results of ① and ② indicate that due to the unique structure of phosphorus and nitrogen elements, the ring structure of phosphorus nitrogen compounds is inserted into the main chain of the EP molecular structure to inhibit the flammability of EP; at the same time, the inhibitory effect is in line with the inhibition of phosphorus nitrogen The flammability and other properties produce a synergistic effect, which makes the flame retardancy, environmental protection and safety of the system more ideal. Conclusion: The novel spiral ring-shaped phosphorus nitrogen compound/epoxy resin system has excellent heat and flame retardant properties, and is bound to become an excellent replacement material for fire, heat, safety, and high-performance materials.


4. Fly ash filled maleated castor oil/epoxy resin composite


Maleated castor oil (MACO): epoxy resin (EP)=1:1 (weight ratio, the same below) was mixed to prepare a blend. Then use 1% MACO: the above blend = 1:1, and mix 1% MACO with 100% EP, and use 1% [Note] diethylene triamine as the curing agent ([Note]: the proportion of the total weight of the resin) , Carry out polycondensation reaction under proper curing conditions. The EP molecule/MACO substrate produces an interpenetrating network structure. Filling the base material with MACO, the results show that: Compared with the pure EP system, the impact strength and damping performance of the above-mentioned filling system are greatly enhanced.

Source:https://www.up-resin.com/

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