Effects of substituted aromatic heterocyclic phosphate salts on properties, crystallization, and melting behaviors of isotactic polypropylene

Abstract

Nucleation effects of 2,2Ј-methylene-bis (4,6-di-tert-butylphenyl) phosphate metal salts as a nucleating agent for isotactic polypropylene (iPP) were investigated with differential scanning calorimeter and polarized optical microscope, and their effects on mechanical, optical, and heat resistance properties of iPP were also studied. The results showed that monovalent metal salts of substituted aromatic heterocyclic phosphate such as sodium salt, lithium salt, and potassium salt had a good performance. With 0.2 wt % of sodium salt, lithium salt, or potassium salt incorporated into iPP, the crystallization peak temperature of iPP could be increased by 13.5, 13.6, and 15.0°C, respectively; the mass fraction of crystallinity of iPP could be increased by about 5%; and crystallization rate was enhanced increasingly. Meanwhile the tensile strength and flexural modulus of iPP could be increased by about 10 and 30%, respectively, and the clarity and heat distortion temperature of iPP could also be improved significantly. But bivalent and trivalent metal salts of substituted aromatic heterocyclic phosphate had little effect on properties of iPP. Meanwhile the morphology study showed that the addition of monovalent sodium salt could decrease the spherulite size of iPP significantly.

Synthesis and characterization of polypropylene-based polymer hybrids linking poly(methyl methacrylate) and poly(2-hydroxyethyl methacrylate)

“…8(b) also showed the same tendency of the peak crystallization temperature and particularly, the hybrid with higher MMA content (PP-PMMA3, 45.5 wt%) was very effective for increasing the melting temperature. These phenomena show that the well-dispersed PMMA domains also worked as efficient nucleating agents for the crystallization of PP matrix like inorganic nanoparticle, clay and organic salts [32][33][34].…”

Injection moulding of long glass fibre reinforced poly(ethylene terephtalate): Influence of carbon black and nucleating agents on impact properties

“…Such a better efficiency of sodium benzoate (R2) compared to phosphate based (R3) nucleating agent may be surprising. Indeed, according to the literature, sodium 2,2!-methtylene-bis(4,6-di-tert-butylphenyl)phosphate (R3) is likely to induce smaller spherulites than sodium benzoate (R2) in non-reinforced plastics [28,29]. However, in the case of fibre-reinforced plastics, a more perfect crystalline structure (small spherulite sizes, homogeneous spherulite structure, possibly transcrystalline interphase -as expected in the case of R3) increases the internal stresses in the fibre/matrix interface region and therefore the material brittleness [10].…”

“…Besides, nucleating agents (e.g. most commonly carboxylate or phosphate ester salts, and sorbitol acetals) are often added to semi-crystalline polymers such as PET [24][25][26][27] or PP [28,29] in order to modify the crystallisation kinetics and mechanism (increase of the crystallisation rate, leading to a faster polymer solidification), consequently leading to injection moulding cycle time reduction. In particular, PET is characterised by a very slow crystallisation and nucleating agents are often added to control a more homogeneous structure through a uniform spherulite size more than to increase the degree of crystallinity of the polymer.…”

“…Sodium benzoate nucleating agent is wellknown to substantially increase the crystallization rate of poly(ethylene terephtalate) at higher temperature and to accelerate crystallization even more at lower temperature with an additional improvement of molecular mobility of PET chains, but the increase of crystallization rate is limited by the fact that sodium benzoate may be only partially soluble in PET matrix [26,27]. The sodium 2,2!-methtylenebis(4,6-di-tert-butylphenyl)phosphate nucleating agent is usually used to increase the crystallization rate of polyolefins, polyamides and PET; it may induce smaller spherulites than sodium benzoate at higher crystallization temperature with shorter crystallization half time [28,29]. On the other hand, the nucleating agents strongly influence the crystalline zone between the fibre and the matrix.…”

Isothermal Crystallization Behaviors of Isotactic Polypropylene Nucleated with Nucleating Agent Bicyclic [2,2,1] heptane di-carboxylate

“…Addition of nucleating agents into iPP is an effective method to improve mechanical and optical properties, which are related to crystallization and morphology. [6][7][8][9][10][11][12][13][14][15] Bicyclic [2,2,1] heptane di-carboxylate (commercial product name: HPN-68) is a novel nucleating agent that was developed by Milliken Chemical Co.…”