Poly1‐hexene: New impact modifier in HIPS technology

Abstract

Poly1-hexene was prepared using a conventional heterogeneous Ziegler-Natta catalyst and its stereoregularity was characterized using 13 C-NMR analysis. New kind of high impact polystyrene (HIPS) was prepared by radical polymerization of styrene in the presence of different amounts of synthesized poly1-hexene (PH) as impact modifier (HIPS/PH) and compared with conventional high impact polystyrene with polybutadiene (HIPS/PB) as rubber phase. Scanning electron microscopy (SEM) revealed that the dispersion of poly1-hexene in polystyrene matrix was more uniform compared with it in HIPS/PB. The impact strength of HIPS/PH was 29-79% and 80-289% higher than that in HIPS/PB and neat polystyrene, respectively. FTIR was used to confirm more durability of HIPS/PH samples toward ozonation. To study the effect of rubber type and amount on the T g s of polystyrene, differential scanning calorimetry was employed. Results obtained from TGA demonstrated higher thermal stability of HIPS/PH sample in comparison with conventional HIPS/PB one. Our obtained results suggest new high impact polystyrene that in all studied aspects has better performance than the conventional HIPS.

New high impact polystyrene: Use of poly(1‐hexene) and poly(1‐hexene‐co‐hexadiene) as impact modifiers

“…This dilatational stress increased free volume in the rubbery phase and allowed reduction of the relaxation time of the rubbery chains and therefore, reduced the T g of the corresponding phase . Another important point is that lowering of T g is the proof of appropriate dispersion of plasticizing rubber particles in the PS matrix …”

“…6 Another important point is that lowering of T g is the proof of appropriate dispersion of plasticizing rubber particles in the PS matrix. 8 DSC analysis was performed to confirm the reduction of T g of rigid PS matrix upon blending with elastomer particles (see Figure 8). Kim and his coworker reported that glass transition temperature of PB remains essentially unchanged with weight fraction in the PS/PB blends; however, the T g of PS changes considerably by altering its content.…”

“…To obtain an ideal blend with improved properties, the nature and amount of the rubber‐reinforcing phase are of critical importance. In the past few decades, using filler/rubber systems, focusing on polyolefin‐type rubbers (such as polybutadiene [PB] and ethylene propylene diene monomer [EPDM]) has attracted a lot of attentions . Among the mentioned rubbers, PB was introduced as the most important one in PS toughening; however, its degradation is a major problem in the related blends.…”

“…It was found that PH, with molecular weight higher than M w = 200 000 g/mol, has a T g of about −45°C and is amorphous in nature. These mentioned factors would make this rubber prone in PS toughening technology …”

“…These mentioned factors would make this rubber prone in PS toughening technology. 8 In this work, the PS/PB, PS/PH, and PS/poly(hexene-cohexadiene) (PS/COPOLY) blends were prepared via melt blending method in an internal mixer to study mechanical and morphological properties as a function of the blend composition. Investigation on toughening behavior of higher α-olefin polymers in PS matrix via melt blending is accomplished for the first time, according to the best of our knowledge.…”