Design And Research On Optical Limiting Material Based On Porphyrins/Poly(Aryl Ether Ketone)S

With modern laser technology appearing, the light source of the high intensity andexcellent coherent property was obtained. For a growing need in nonlinear optical(NLO) materials, the relative theory to explain the nonlinear optical phenomenon wasdeveloping rapidly. The laser weapons coming into the world have drawn thewide-ranging attention all over the world, especially for passive-mode optical limiting(OL) applications to protect optically sensitive devices and human eyes from laserdamage in both civilian and military applications. Optical limiters as a special kind ofmaterials, which reduce the intensity of hostile lasers by its instantaneous filteringaction, meanwhile possed the high thermal stability and outstanding mechanicalproperties were devoted the deep research.Poly (aryl ether ketone)s (PAEKs), due to its excellent mechanical properties,thermal stability, electrical and chemical resistance properties, were made a candidatefor advanced materials. Recently, the functioning of PAEKs was the focus research inthe field, in which the most effective method was introducing the groups with thespecial functions into the PAEKs matrix by physics or chemical ways. In order toretain the excellent properties of the materials, the choice of the functioning groupsintroduced into PAEKs shown greatly significant, which in the main principle need tomatch the excellent properties of PAEKs, such as the thermal stability, chemicalstability and so on.Porphyrins, as one of the most promising candidates existing in the nature, hadbeen widely studied and applied, which acted on the life of animals and plantsimportantly, and was used as the reaction centre of simulating photosynthesis, orantenna system to capture light, synthesizing the molecular device, magnetic material, optical limiters, highly active catalytic agent, and antineoplastic drug, ect. Mostporphyrin materials possed weak solubility in the organic solvent, existing theunfavorable aggregation in the highly dense system, which limited the application ofporphyrin. In recent years, great efforts were made in utilizing porphyrin to developthe efficient OL materials, which could have a large ratio of the excited-state toground-state absorption cross sections (κ=σex/σ0). In order to be convenient formaterial processing, the most effective improving was introducing porphyrin into thePAEKs matrix by blending or branching, which need to meet the demand of retainingthe excellent properties of the materials, in case that increasing the content ofporphyrin as more as possible, we need to solve its dispersion problems in polymermatrix.One of the current challenges was probably the difficulty of handling thematerials in liquid form. The incorporation of porphyrin units into the framework ofthe hyperbranched PAEKs (HPAEKs) could not only help to solve the dissolutionprocessing problems, a necessary condition for avoiding aggregation, but alsoendowed resultant polymers with novel properties. Retained the excellent propertiesof the materials, particularly in thermal stability, preparation of the required NLOactive materials for practical optical limiters was the focus research in the field.First of all, we had synthesized tetraphenylporphyrin (TPP). Made TPP and6FPAEK solution blended, cast films. And a series of characterization of thecomposite films were carried out. TPP had nonlinear optical properties, at the sametime the thermal stability of TPP and6FPAEK were matched. As a result, thecomposite films had nonlinear optical properties and good thermal stability. Themechanical properties of the composites films were decreased by the instruction ofTPP. It is mainly due to the aggregation phenomenon occurred, when TPP reached acertain concentration in the solution, simple solution blending did not make the TPPwell dispersed in the polymer, so that the mechanical properties of the compositefilms declined. It was an effective way to obtain the optical limiting materials byblending filler materials with optical limiting property and polymer. But, this couldnot be done by no loss of performance, this problem could be solved by uniformlydispersing fillers in the polymer matrix. Further more, in order to obtain Porphyrin/PAEKs optical limiting materials withgood performance, we prepared two series of PAEKs oligomers, with4-hydroxyphenyl porphyrin (THPP) linked in PAEKs segment. The obtained polymerhad good solubility, excellent thermal stability and the enhanced mechanicalproperties. Made oligomers of PAEKs capped or crosslinked by THPP could producesignificant enhancement of the mechanical properties of the composite material, inparticular the crosslinked ones, a substantial increase in mechanical properties of thematerial; The non-linear optical properties and optical limiting properity of thepolymers were given by introduction of THPP, made PAEKs to achieve abreakthrough in optical limiting field; χ(3)and optical limiting capacity of thepolymers increased with porphyrin content; Polymer backbone containing electrondonating groups can strengthen its nonlinear performance; in6FPAEK series polymer,thermal stability and mechanical properties were stronger than that of BPAPAEKseries polymer, and the gap between their nonlinear optical performance was quitsmall,6FPAEK series polymer was more suitable for application as a high damagethreshold of optical limiting materials.In order to get better dispersion of porphyrin molecules in PAEKs matrix, weprepared a series of Porphyrin-containing hyperbranched poly (aryl ether ketone)s andits metal derivatives. The polymer obtained had good solubility and excellent thermalstability; Z-scan and optical limiting test results shown that the non-linear opticalproperties and optical limiting properity of the polymers were given by introductionof THPP; χ(3)and optical limiting capacity of the polymers increased with porphyrincontent; The hyperbranched structure made porphyrin optical limiting ability to bemore efficient, in the adverse conditions that the porphyrin content was less than thatof porphyrin capped PAEKs, χ(3)and optical limiting ability exhibited much better;The hyperbranched structure allowed better dispersion of the porphyrin molecule in athree-dimensional network structure of the polymer, to reduce the occurrence of theaggregation phenomenon. When the porphyrin content in polymer was similar, thehyperbranched polymer had stronger optical limiting capability.In order to improve Porphyrin content in PAEKs, make Porphyrin get optimized distribution in PAEKs. We synthesized5,10-bis (4-hydroxyphenyl)-15,20-diphenylporphyrin (Cis-DHDPP) and got a series of PAEKs contained Porphyrin. The obtainedpolymers had good solubility, excellent thermal stability, good mechanical properties,χ(3)value reached10-12esu (0.5mg mL-1), with certain optical limiting property; ThePorphyrin content in PAEKs was highly improved, at the same time, Cis-DHDPP hada unique molecular structure type, made Cis-DHDPP disorganized dispersed inPAEKs segment, avoided the occurrence of aggregation and improved the opticallimiting ability of the material.