Synthesis Of Double Guests Co-intercalated Layered Double Hydroxides And Their Application In Pp Composite

Polypropylene(PP)has been widely used in chemical industry,light industry,agriculture,construction and other fields because of its rich source,light weight,corrosion resistance,low processing cost and excellent physical mechanical properties.It is one of the four general plastics and plays an important role in the production and life of humanbeings.In the process of PP production,pigments,light stabilizers,thermal stabilizers and other functional additives are added in PP to afford PP products with color,improve the performance of PP products and enhance the quality of PP products.However,these additives are small organic molecules,which suffers from poor thermal stability,volatility,easy migration and other shortcomings,greatly affecting the quality and performance of PP products.Therefore,it is very important to prepare functional additives with good thermal stability,non-volatility and resistance to migration for PP products in order to improve their quality and performance.Layered Double Hydroxides(LDH)are a kind of layered anionic clays which possess the advantages of controllable chemical composition and charge density,anion exchange ability,good thermal stability,and easy production,and they can be used as flame retardants,thermal stabilizers,light stabilizer and other functional additives in the field of plastics.However,the single function of prepared LDH materials greatly restricts their application in the field of plastics because only one kind of functional guest is exist in the interlayer.In this thesis,we proposed the idea of preparing multi-guests co-intercalated LDH to overcome this drawback based on the controllability of the composition and structure of LDH.The thermal stability of the guest anions can be improved through protection the guest anions by the LDH host layers;the immobilization of guest anions through host-guest interactions can restain the voltility and migration of guest anions;the function of LDH materials can also be adjusted by changing the kind and ratios of interlayer gust anions.At first,organic-inorganic hybrid pigments with controllable colors were prepared by co-intercalating Acid Green 25(AG25)and Acid Yellow 25(AY25)into LDH according to the principle of chromaticity.Then,bi-functional materials with function of pigment and U-V barring were prepared by co-intercalating Acid Yellow 11(AY11)and a series of UV absorbers into the interlayer of LDH.Finally,light stabilizer with enhanced anti-aging performance was prepared by co-intercalating sorbic acid and UV absorber into the interlayer of LDH.The main contents and conclusions of the paper are as follows.A series of green pigments with supramolecular structure were constructed by co-intercalating AG25 and AY25 into the interlayer of ZnAl-LDH through co-precipitation method.The effects of composition and structure on the color and thermal stability of the hybrid pigments were investigated.The introduction of AY25 significantly improved the color of the hybrid pigment based on AG25 intercalated LDH,and the color was changed from blue to green by co-intercalation method.The color of the hybrid pigment can be facilely controlled by adjusting the molar ratio of AY25/AG25 in the interlayer.There exists host-guest and guest-guest interactions in the hybrid pigments system.The host-guest interactions between LDH layers and guest anions enhanced the thermal stability of AY25,resulting in a kind of hybrid pigment which can tolerate 250℃.The guest-guest interactions between AY25 and AG25 plays a key role on the color of the hybrid pigments.The obtained green hybrid pigments can be used as colorant to color PP,which expand the application field of AG25 and AY25.A series of bi-functional materials with function of pigment and UV barring were assembled by co-intercalating AY 11 and a series of UV absorbers(2-hydroxy-4-methoxy-5-sulfo benzophenone,cinnamic acid,salicylic acid,p-aminobenzoic acid and phenyl benzimidazole sulfonic acid)into the interlayer of ZnAl-LDH through separated nucleation and aging steps method.The effects of composition and structure on the thermal stability,UV-vis absorption ability and UV barring ability of the bi-functional materials were investigated.The intercalation significantly improved the thermal stability of AY11,and a series of bi-functional materials with excellent thermal stability were obtained.The bi-functional materials not only can be used as pigments to color PP,but also enhanced the thermal stability of PP composites.Besides,they also offered UV barring ability to PP composites,greatly improving the anti-aging performance of PP.A kind of light stabilizer with enhanced anti-aging performance was prepared by co-intercalating a weak reductant(sorbic acid)and an UV absorber(2-hydroxy-4-methoxy-5-sulfo benzophenone)into the interlayer of MgAl-LDH through separated nucleation and aging steps method.The effects of composition and structure on the anti-aging performance of the light stabilizer were investigated.There exists host-guest and guest-guest interactions in the light stabilizer with intercalation structure,and the obtained light stabilizer possesses good UV barring ability.The prepared light stabilizer not only enhanced the thermal stability of PP composites,but also significantly improved the anti-aging performance of PP.The obtained results revealed that sorbic acid and UV absorber co-intercalated LDH has better anti-aging performance than sorbic acid intercalated LDH and UV absorber intercalated LDH,indicating there exists synergistic anti-aging effects between sorbic acid and UV absorber.