Comparison of block-copolymer with soap in micelle formation

Simple equations for the micelle formation of block-copolymers are derived from the concept of Leibler-Orland-Wheeler. The size of micelle, core, and corona are expressed in terms of chain length of block-copolymers and homopolymers and the interaction parameters of the components based on the balance between the interface energy and the strain energy of the polymer chains. These equations are extended to the soap micelle by taking the electric repulsion of soap ions into consideration. Various data on the micelle size, the solubility, the critical micelle concentration, the critical solution temperature, and the salt effect can be explained quantitatively by the theory. The solubilization ability is also discussed.     

Creating super-tough and strong PA6/ABS blends using multi-phase compatibilizers

PA6/ABS blends with excellent mechanical properties are prepared using combination of two effective multi-phase compatibilizers, where finely dispersed domains with unique encapsulation structures are generated for the synergistic improvement in tensile and impact performances.     

聚乙烯-g-聚苯乙烯对线性低密度聚乙烯/聚苯乙烯共混物机械性能和发泡行为的影响

以通过开环易位聚合、加氢反应和原子转移自由基聚合技术结合制备的聚乙烯-g-聚苯乙烯(PE-g-PS)作为增容剂,研究了加入不同PS支链长度的PE-g-PS对于线性低密度聚乙烯/聚苯乙烯(LLDPE/PS)共混物的机械性能和发泡行为的影响。 以典型组成m(LLDPE):m(PS)=70:30共混物为例,考察了PE-g-PS对共混物拉伸性能的影响。 相对于二元共混物,增容剂的加入使得断裂伸长率、拉伸强度和屈服强度皆提高,且含长PS支链的增容体系提高更明显。 采用超临界CO₂釜式发泡工艺,考察了PE-g-PS中PS支链长度对共混物发泡行为的影响。 结果表明,相对于短PS支链体系,加入PE-g-PS_1.59k(PS相对分子质量为1590)后的泡孔结构更加均一,完全没有“缝隙”形貌的出现。 当发泡温度降至80 ℃时,即使存在LLDPE发泡空间限制作用(LLDPE无法发泡),加入支链长度更长的PE-g-PS_1.59k后泡孔分布也更加均一。     

Synthesis,Characterization and Properties of Novel Amphiphilic Phosphated Ionomers by Ring‐Opening Reaction of Epoxidized Styrene‐Butadiene‐Styrene Triblock Polymer

A method for synthesis of novel phosphated ionomer of (styrene‐butadiene‐styrene) triblock polymer (SBS) from epoxidized SBS was developed. The optimum conditions for the ring‐opening reaction of the epoxidized SBS with aqueous solution of disodium hydrogen phosphate were studied. It was found that during the ring‐opening reaction phase transfer catalyst, ring‐opening catalyst and pH regulator were necessary to enhance the conversion of epoxy groups to ionic groups. The products were characterized with Fourier Transform Infrared Spectrophotometry (FTIR) and transmission electron microscopy (TEM). Some properties of the phosphated ionomer were studied. With increasing ionic groups or the ionic potential of the cation of the ionomer, the water absorbency emulsifying volume and the intrinsic viscosity of the ionomer increase, whereas the oil absorbency decreases. The ionomer possesses excellent emulsifying property, as compared with the sulfonated ionomer. The disodium phosphated ionomers in the presence of 10% zinc stearate showed better mechanical properties than the original epoxy SBS. Optimum mechanical properties occurred at the ionic group content of 0.95 mmol/g ionomer. When the ionomer was blended with crystalline polypropylene, a synergistic effect occurs with respect to the tensile strength. The ionomer behaves as a compatibilizer for blending equal amount of SBS and oil‐resistant chlorohydrin rubber (CHR) to form an oil resistant thermoplastic elastomer. SEM microphotographs indicated enhanced compatibility between the two components of the blend in the presence of the ionomer.     

Synthesis of Maleated Ionomers via Ring‐Opening Reaction of Epoxidized (Styrene‐Butadiene‐Styrene) Triblock Copolymer with Potassium Hydrogen Maleate and Study of their Properties

A novel method for synthesizing maleated ionomer of (styrene‐butadiene‐styrene) triblock copolymer (SBS) from epoxidized SBS was developed. The epoxidized SBS was prepared via epoxidation of SBS with performic acid formed in situ by 30% H₂O₂ and formic acid in cyclohexane in the presence of polyethylene glycol 600 as a phase transfer catalyst. The maleated ionomer was obtained by a ring‐opening reaction of the epoxidized SBS solution with an aqueous solution of potassium hydrogen maleate. The optimum conditions for the ring‐opening reaction and some properties of the ionomers were studied. It is necessary to use phase transfer catalyst, ring‐opening catalyst and a pH regulator (dipotassium maleate) for obtaining the epoxy group conversion over 90%. The product was characterized by FTIR spectrophotometry and transmission electron microcroscopy (TEM) to be an ionomer with domains of maleate ionic groups. With increasing ionic groups, the water absorbency and the dilute solution viscosity of the ionomer increase, whereas the oil absorbency decreases. The tensile strength and ultimate elongation of ionomers increase with ionic group content and are higher than those of the original SBS without using any ionic plasticizer, which is usually used with the sulfonated ionomer. The ionomers with 1.2–1.7 mmol ionic groups/g exhibit optimum mechanical properties and behave as thermoplastic elastomers. The ionomer can be used as a compatibilizer for the blends of SBS with oil resistant chlorohydrin rubber (CHR). Addition of 3 wt% ionomer to the blend can increase the tensile strength and ultimate elongation of the blend optimally. The compatibility of the blends enhanced by adding the ionomer was shown by scanning electron microscopy (SEM). The blend of equal weight of SBS and CHR compatibilized by the ionomer behaves as a toluene resistant thermoplastic elastomer.