Compatibilization of low-density polyethylene/polystyrene blends by segmented EB(PS-block-EB) n block copolymers

Abstract

Summary Hydrogenatedsegmented poly [butadiene-block-(styrene-block-butadiene)n] block copolymers, which were developed by use of a polymeric iniferter technique, were tested on their compatibilizing effectiveness for (10/90) LDPE/PS blends. They were found to be effective compatibilizers for this mixture, already giving a pronounced improvement in both tensile strength and strain of the blend at block copolymer concentrations of one percent. A concentration of five weight percent of segmented block copolymer provided a tenfold improvement in blend toughness. The effectiveness of the segmented block copolymers was found be dependent on the block copolymer composition. Block copolymer compositions of close to 50:50 EB:PS gave the best results. IntroductionPolymer blends could provide materials having a wide variety of mechanical properties by adjusting the type and quantity of polymers in the mixture. However, because most polymers are immiscible, the blend components usually phase separate into macroscopic domains and consequently show poor mechanical properties, particularly regarding ductility. It is well known that block or graft copolymers, containing blocks of the same chemical structure as the hetero phases in an incompatible binary polymer blends, are capable of compatibilizing these polymer mixtures (1-4). When localized at the interface between the immiscible polymers, the block copolymers lower the interfacial tension, thereby dispersing the polymer blend into smaller domains due to reduced coalescence of the stabilized particles. Consequently, the blends may show improved ductility, because of enhanced force transfer between the different phases.Although the compatibilization of blends has been investigated extensively, the effect of compatibilizer architecture is still rather questionable. The number of blocks appear to playa significant role here. In various experimental studies quite different effects of the number of blocks in a block copolymer on its compatibilizing effectiveness have been reported. For example, in a paper by Teyssié et aI. diblock copolymers have been found to be more efficient compatibilizers than triblock copolymers (5), while in some other works quite the opposite effect is presented (6-8), and another one states that there is no difference in compatibilizing effectiveness between di-and triblock copolymers (9).

Compatabilization of polystyrene/polypropylene blends by styrene-butadiene block copolymers with differing polystyrene block lengths

“…In earlier articles, 16,18 we published surprisingly good results with styrene (S)-butadiene (B) pentablock copolymers in the compatibilization of PS/ polypropylene (PP) blends. Kroeze et al 21 found hydrogenated segmented poly[B-block-(S-block-B)n] multiblock copolymers to be effective compatibilizers for low-density polyethylene/PS blends.…”

“…Two procedures are usually utilized in compatibilization: (1) use of functionalized polymers or reactive compatibilizers to form chemical bonds between the blend components and (2) addition of a block copolymer (BC) or a graft copolymer, the blocks of which have the same or similar chemical composition as the homopolymers in a blend of immiscible polymers. Although reactive compatibilization is now widespread, [1][2][3][4][5][6] BCs or grafted copolymers are still the most suitable compatibilizers [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] in the compatibilization of polyolefin/polystyrene (PS) blends.…”

Thermoplastic elastomer gels. I. Effects of composition and processing on morphology and gel behavior

“…Complementary theoretical [1][2][3][4][5][6] and experimental [7][8][9][10] efforts are continually directed at enriching the current understanding of block copolymer phase behavior and dynamics under a wide variety of conditions. The ultimate objective of such efforts is to produce microstructured polymeric materials with the tailored properties needed to develop new, 11,12 as well as improve existing, 13 applications. Addition of a solvent to a microphase-ordered block copolymer affords a viable route by which to probe the order-disorder transition of highly segregated copolymers, 14 but is seldom employed 15 in morphological studies of ordered block copolymers.…”

Pengaruh Anti Oksidan Terhadap Kestabilan Sifat Fisis Bahan Polipaduan Polipropilena-Karet Alam: II. Studi Kristalinitas dan Struktur Molekul

“…Sifat akhir bahan polipaduan yang dihasilkan sangat bergantung pada karakteristik polimer pengisi, meliputi konsentrasi dan jenis, dan sifat adesi antar muka matrik-pengisi yang menentukan kompaktibilitas polipaduan serta tingkat penyebaran polimer pengisi dalam matrik. Sejauh ini telah dilakukan beberapa penelitian bahan polipaduan yang mengkaji sifat mekanik [1][2][3], sifat kompaktibilitas polipaduan [4], sifat termal [1,5,6].…”

“…Untuk mengetahui pengaruh pemberian bahan anti oksidan irganok 1076 terhadap struktur kristal bahan polipaduan yang mengalami perlakuan penjemuran di alam terbuka (di bawah sinar matahari) dapat diketahui dengan menghitung nilai derajat kristalinitas dari difraktogram bahan polipaduan PP-KA dan PP-KAIrganok 1076 8%. Hasil penghitungan derajat kristalinitas dari kedua polipaduan dengan metode standart dalam ditunjukkan pada Tabel 1.blends), sedangkan PVC-ABS termasuk polipaduan jenis kompak (miscible blends) [2,4]. Dalam penelitian yang mengkaji sifat tarik dari polipaduan telah dilakukan eksperimen pengukuran kebergantungan tegangan luluh, kekuatan tarik dan regangan patah serta modulus elastik pada konsentrasi bahan pengisi.…”