Preparation And Study Of Black Perylene Pigment

Black perylene pigments have recently generated interest in the field of textile dyes,automotive paints and infrared shielding,because of their excellent thermal,light,chemical stability,a high infrared reflectivity,non-toxic environmental protection and so on.However,there were few reports about the research on the physicochemical properties of different perylene pigments.This thesis studies the relationship between the structure and the infrared properties of different black perylene pigments through simulation calculations and preparation experiments.By adjusting the substituents of pigment,the black perylene pigment that has high thermal infrared reflectance and low brightness was prepared.Research indicates that the molecular dipole moment was the main influencing factor affecting infrared reflection.The research of this thesis includes:1)The relationship between the molecular structure and the infrared reflectance,the UV-Vis spectral properties of the different black perylene pigments were calculated basing on the density functional theory.By changing substituting group,the molecular dipole moment,the frequency of molecular vibration,the intensity of the infrared spectrum band and the infrared reflectance increases.At the same time,the introduction of imide substituents and the π electrons of the molecule form a conjugated system,which reduces the energy difference between the molecular ground state and the excited state,resulting in redshift of the UV-Vis spectrum.2)The black perylene pigments with three different substituents were synthesized by manipulation of the temperature and time,the substituent groups were as follows: phenylamino group,phenylethylamino group and 4-methoxybenzylamino group.The molecular structure,purity,chemical properties,morphology and chromaticity were characterized.The results show that the average infrared reflectance of the three black perylene pigments at 8-14 μm were 0.11,0.13 and 0.34.At the same time,the perylene pigments have three absorption peaks,the λmax were as follows: 589 nm,657nm and 702 nm.Comparing with the precursor PTCA,the λmax shows bathochromic effect.The fracture surface indicated that the pigment particles have high crystallinity,and the particle size is distributed.The color analysis showed that the L* of the pigments were between 10 and 15,and the color was black.The L* of the pigment with 4-methoxybenzylamine was 10.41,which could reduce the coating brightness.3)The experications verified that the density functional simulation were correctness.The infrared spectrum was compare with experimental ones with a good agreement between them,and the simulation results were effective.In view of the Lambert’ theory,the fitted curves for the dipole moment to thermal infrared reflectance were plotted,it shows that the molecular dipole moment can have effects on absorption coefficient,that would affect the infrared reflectance of the coating.In this thesis,the perylene pigment with 4-methoxybenzylamine was prepared by simulation calculations and preparation experiments.It’s reflectance of 8-14μm was 0.34,the L* was 10.41.It was a kind of organic black pigment with high tinting force and high infrared reflected.It applies to the coating preparation with low-brightness and high-infrared reflective.