Study On Preparation And Nucleation Efficiency Of Carboxylate As Nucleating Agents Of Polypropylene Based On C5Fraction

The cracking C5Fraction is the byproduct of the ethylene cracker. The high value-added fine use is the utilization trend of C5Fraction. That will develop a new utilization direction to introduce C5Fraction into the field of additives for polyolefin and improve the utilization of petroleum resources. By the analysis of the chemical structure of the existing nucleating agents, it is found that some of the amide and the carboxylic acid salts are effective nucleating agents of polypropylene. The functional groups for amide and carboxylate are the amide and carboxyl groups. Imaging the two functional groups are designed to one molecular, they may generate synergy effect and be a novel efficient nucleating agent of polypropylene. Based on the design ideas, combined with the application status and trends of the China’s ethylene cracker byproducts C5Fraction, cyclopentadiene of the C5fraction was used as raw material, and then reacted with maleic anhydride to synthesize the norbornene dicarboxylic acid anhydride. Then a novel nucleating agents of polypropylene, bicyclo[2.2.1]hept-5-ene-2--amide-3-carboxylate, which simultaneously have the structure of amide and were designed and synthesized based on norbornene anhydride and amide. Meanwhile, a novel nucleating agents which can simultaneously increase thermal stability of iPP were designed and synthesized by the use of chlorendic anhydride, which is a derivative of cyclopentadiene.Firstly, benzylamine with an aromatic group was chose, and then reacted with norbornene dicarboxylic anhydride to synthesize norbornene benzylamide acid. Then norbornene benzylamide acid lithium, sodium, potassium, magnesium, calcium, zinc, barium and aluminum salts were synthesized by the acid-base neutralization reaction and metathesis reaction. The effects of these nucleating agents on the mechanical properties, optical properties and crystallization behavior of iPP were investigated. An effective a-crystal form nucleating agent, sodium bicycle [2.2.1] hept-5-ene-2-benzoylamide-3-carboxylate (BHBC11) was found. The concentration effects of BHBC11were further investigated. The results showed the optimal concentration of BHBC11was0.1wt%. Compared with pure iPP, the tensile strength and flexural modulus of nucleated iPP increased9%and30%, respectively. The crystallization peak temperature (Tp) of nucleated iPP increased10℃. However, the haze value of iPP was not decreased by the addition of BHBC11. Furthermore the non-isothermal crystallization kinetics were studied by Caze method. The Avrami exponents of both pure iPP and nucleated iPP are about4, which indicates that BHBC11change nucleation and growth mode of iPP. Nucleation mode was change, which has been proved by means of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The results showed that the addition of BHBC11can decrease the spherulite size of iPP remarkably which indicated nucleation mode of nucleated iPP was heterogeneous nucleation. However, the Avrami exponent of nucleated iPP did not change compared with pure iPP, inferring that the growth mode of nucleated iPP was changed. For proving that, scanning electron microscopy (SEM) was used to observe the crystal morphology. The bundle crystals were found, which proved our inference. The nucleating agent BHBC11improved the crystallization activation energy of iPP. With the nucleating agent content, the trend of the crystallization activation energy was entirely consistent with that of static viscosity of iPP. The phenomenon indicated that BHBC11improved the viscosity of the polypropylene, thus limiting the movement of the polypropylene segment, resulting in the crystallization activation energy increases.Secondly, an aliphatic amines, dodecylamine, was chose, and then reacted with norbornene dicarboxylic anhydride to synthesize norbornene dodecylamine acid. Then norbornene dodecylamine acid lithium, sodium, potassium, magnesium, calcium, zinc, barium and aluminum salts were synthesized by the acid-base neutralization reaction and metathesis reaction. Their effects on the mechanical properties, crystal form and crystallization behavior of iPP were investigated. An effective β nucleating agent, zinc bicycle [2.2.1] hept-5-ene-2-dodecylamine-3-carboxylate (NBDA-30) was screened. The formula of NBDA-30is determined to be (C21H34O3N)2Zn·H2O by the analysis of FTIR, elemental analysis, TGA and DSC. The concentration effects of NBDA-30were further studied. the results showed that the NBDA-30could significantly improve the impact strength of the polypropylene. When NBDA-30content was0.8wt%, the impact strength of the polypropylene increased from31.8J/m to91.0J/m, which was nearly3-fold compared with pure iPP. Meanwhile the tensile strength and flexural modulus of iPP were not significantly affected. The (3-crystal content (k value) of iPP firstly increased and then decreased with the increasing of NBDA-30content. When the content of NBDA-30was0.2wt%, the k value reached the maximum value81.7%, which indicated that the nucleating agent NBDA-30was highly efficient β crystal nucleating agent of iPP. NBDA-30could significantly improve the crystallization peak temperature and obviously reduce the size of the spherulites of the polypropylene. Caze equation was used to study non-isothermal crystallization kinetics of pure iPP and iPP nucleated with NBDA-30. The Avrami exponents of nucleated iPP calculated from Caze equation were higher than that of pure polypropylene, and their values were about4. The results indicated that NBDA-30changed the nucleation and growth mode of iPP because heterogeneous nucleation behavior of NBDA-30had been proved by DSC and POM. Finally, a novel (3nucleating agent of isotactic polypropylene (iPP), the potassium salt of1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (CA-19), was found and its effects on the mechanical properties, content of β crystal, and crystallization behavior of iPP were investigated. The results showed the content of β crystals of nucleated iPP (kβ value) can reach46.3%with0.25wt%CA-19. The impact strength and crystallization peak temperature of nucleated iPP were greatly increased. Compared with pure iPP, the impact strength of nucleated iPP can increase2times and the crystallization peak temperature (Tp) of nucleated iPP increased7℃. At the same time, it was found that CA-19could greatly improve the thermal stability of iPP. Compare with pure iPP, the5wt%thermal composition temperature of nucleated iPP increased about10℃and that of50wt%increased about25℃. The results indicated that CA-19had dual role for iPP, simultaneously improving the nucleation and the thermal stability of iPP. The spherulite size of the nucleated iPP was dramatically decreased compared to that of pure iPP. The Caze method was used to investigate the non-isothermal crystallization kinetics of nucleated iPP and the crystallization activation energy was obtained by the Kissinger method.