In this paper, we investigated the influence of MDBS, DMDBS, the synergist of MDBS and DMDBS (weight ratio 50/50) to optical, thermal, mechanical properties and morphology of material. | Study on the clarifying additives for high density polyethylene Vietnam Journal of Science and Technology 56 (2A) (2018) 63-68 STUDY ON THE CLARIFYING ADDITIVES FOR HIGH DENSITY POLYETHYLENE Le Thi Bang1, *, Nguyen Phi Trung1, Nguyen Van Khoi2, Tran Vu Thang2, Trinh Duc Cong2, Hoang Thi Phuong2 1 Institute of Research and Development on Novel Materials, 350 Lac Trung, Hai Ba Trung, Ha Noi 2 Institute of Chemistry, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Viet Nam * Email: banghoak6@ Received: 28 March 2018; Accepted for publication: 10 May 2018 ABSTRACT Bis-3,4- dimethyldibenzylidene sorbitol (DMDBS); bis-p-methylbenzylidene sorbitol (MDBS) and the mixture of DMDBS/MDBS (50/50) were studied through optical, thermal, mechanical properties and surface morphology. With the same amount of additive (DMDBS/MDBS mixture and DMDBS) in the material, the results are similar. On the other hand, using an additive mix reduces the cost of production due to MDBS. Furthermore, the additive mixture is used without producing odours. Therefore, the mixture of DMDBS/MDBS (50/50) is chosen. Keywords: polyethylene, bis-3,4-dimethyldibenzylidene sorbitol, bis-p-methylbenzylidene sorbitol. 1. INTRODUCTION High-density polyethylene (HDPE) is widely used today in a large number of applications including packaging, coating and films. The optical, machanical, thermal and chemical properties are significantly affected by the crystallization process [1]. Directed modification of the crystalline morphology during solidification from the melt state in HDPE can alter a wide range of physical properties such as optic clarity [2], shrinkage [3], and cycle time in extrusion and molding [4]. As these properties are directly related to the crystalline morphology of the polymer, directed modification to control the crystallization of HDPE can lead to significant improvements in targeted physical properties. Nucleation and .
