Abstract
In this article, iPP with β-nucleating agent was molded by sequential co-injection molding (SCIM), in which skin and core melt were injected into the mold cavity one after the other. The microstructure and mechanical properties of samples were investigated by polarized optical microscope (POM), wide angle X-ray diffraction (WAXD) and mechanical property test. Results show that plastic parts molded by SCIM have double shear layers due to twice shear induced by filling flow of skin and core melt. In the shear layers especially the layer at the overlap of skin and core material, shear promoted the formation of highly oriented structures (shish-kebabs) but inhibited the produce of β-form. In core layer of skin material and core layer of core material, β crystals are predominant. The combination of oriented structures (shish-kebabs) and β crystals endow iPP with high strength and toughness. This work demonstrates a new approach to achieve high-performance polymer materials based on general plastics by manipulation strategy for morphology and structure.
Similar content being viewed by others
References
Kalay G, Bevis MJ (1997) Processing and physical property relationships in injection-molded isotactic polypropylene. 1. Mechanical properties. J Polym Sci B Polym Phys 35:241–263
Kalay G, Bevis MJ (1997) Processing and physical property relationships in injection-molded isotactic Polypropylene.2. Morphology and crystallinity. J Polym Sci B Polym Phys 35:265–291
Yamaguchi M, Irie Y, Phulkerd P, Hagihara H, Hirayama S, Sasaki S (2010) Plywood-like structure of injection-moulded polypropylene. Polymer 51:5983–5989
Chen YH, Zhong GJ, Wang Y, Li ZM, Li LB (2009) Unusual tuning of mechanical properties of isotactic polypropylene using counteraction of shear flow and β-nucleating agent on β-form nucleation. Macromolecules 42:4343–4348
Wang K, Chen F, Zhang Q, Fu Q (2008) Shish-kebab of polyolefin by “melt manipulation” strategy in injection-molding: a convenience pathway from fundament to application. Polymer 49:4745–4755
Huo H, Li HF, Meng YF, Jiang SC, AN LJ (2004) Crystallization behavior of Isotatic polypropylene under shearing. Polymer Bulletin-Beijing 3:58–66
Somani RH, Hsiao BS, Nogales A, Fruitwala H, Srinivas S, Tsou AH (2001) Structure development during shear flow induced crystallization of i-PP: in situ wide-angle X-ray diffraction study. Macromolecules 34:5902–5909
Somani RH, Yang L, Hsiao BS (2006) Effects of high molecular weight species on shear-induced orientation and crystallization of isotactic polypropylene. Polymer 47:5657–5668
Somani RH, Yang L, Hsiao BS, Agarwal PK, Fruitwala HA, Tsou AH (2002) Shear-induced precursor structures in isotactic polypropylene melt by in-situ Rheo-SAXS and Rheo-WAXD studies. Macromolecules 35:9096–9104
Zhou QX, Liu FH, Guo C, Fu Q, Shen KZ, Zhang J (2011) Shish-kebab-like cylindrulite structures resulted from periodical shear-induced crystallization of isotactic polypropylene. Polymer 522:970–2978
Wang Y, Na B, Fu Q, Men YF (2004) Shear induced shish–kebab structure in PP and its blends with LLDPE. Polymer 45:207–215
Liu Q, Sun XL, Li HH, Yan SK (2013) Orientation-induced crystallization of isotactic polypropylene. Polymer 54:4404–4421
Aboulfaraj M, G'Sell C, Ulrich B, Dahoun A (1995) In situ observation of the plastic deformation of polypropylene spherulites under uniaxial tension and simple shear in the scanning electron microscope. Polymer 36:731–742
Maier C, Calafut T (1999) Polypropylene: the definitive User's guide and Databook. William Andrew, New York
Turner-Jones A, Cobbold AJ (1968) The β crystalline form of isotactic polypropylene. Journal of Polymer Science Part B: Polymer Letters 6:539–546
Samuels RJ, Yee RY (1972) Characterization of the structure and organization of β-form crystals in type III and type IV isotactic polypropylene spherulites. Journal of Polymer Science Part A-2: Polymer Physics 10:385–432
Meille SV, Brückner S (1989) Non-parallel chains in crystalline γ-isotactic polypropylene. Nature 340:455–457
Yang SG, Zhang ZC, Zhang LQ, Zhou D, Wang Y, Lei J, Li LB, Li ZM (2015) Unexpected shear dependence of pressure-induced γ-crystals in isotactic polypropylene. Polym Chem 6:4588–4596
Lovinger AJ, Chua JO, Gryte CC (1977) Studies on the α and β-forms of isotactic polypropylene by crystallization in a temperature gradient. J Polym Sci Polym Phys Ed 15:641–656
Fujiwara Y (1975) The double melting behavior of β-phase of isotactic polypropylene. Colloid Polym Sci 253:273–282
Shi G Y, Zhang J Y, Jing H. (1993) Beta-crystalline form of isotactic polypropylene and method for forming the same. United States Patent 5231126
Kersch M, Schmidt HW, Altstädt V (2016) Influence of different beta-nucleating agents on the morphology of isotactic polypropylene and their toughening effectiveness. Polymer 98:320–326
Takahashi T (2002) Crystal modification in polypropylene fibers containing β-form nucleating agent. Fiber 58:357–364
Varga J (1983) Characteristics of cylindritic crystallization of polypropylene. Macromol Mater Eng 112:191–203
Zhang B, Chen JB, Ji FF, Zhang XL, Zheng GQ, Shen CY (2012) Effects of melt structure on shear-induced β-cylindrites of isotactic polypropylene. Polymer 53:1791–1800
Luo BJ, Li HF, Zhou CB, Zhang WY, Li JQ, He XH, Jiang SC (2016) Mechanistic insights into the shear-induced β-form crystal formation of iPP. Macromol Chem Phys 217:1354–1360
Jacoby P, Bersted BH, Kissel WJ, Smith CE (1986) Studies on the β-crystalline form of isotactic polypropylene. J Polym Sci B Polym Phys 24:461–491
Ding Q, Zhang ZS, Dai X, Li M, Mai KC (2014) Crystalline morphology and mechanical properties of isotactic polypropylene composites filled by wollastonite with β-nucleating surface. Polym Compos 35:1445–1452
Xu X, Li XP, Jin BQ, Sheng Q, Wang T, Zhang J (2016) Influence of morphology evolution on the mechanical properties of beta nucleated isotactic polypropylene in presence of polypropylene random copolymer. Polym Test 51:13–19
Zhang J, Shen KZ, Na S, Fu Q (2004) Vibration-induced change of crystal structure in isotactic polypropylene and its improved mechanical properties. J Polym Sci B Polym Phys 42:2385–2390
Labour T, Vigier G, Séguéla R, Gauthier C, Orange G, Bomal Y (2002) Influence of the β-crystalline phase on the mechanical properties of unfilled and calcium carbonate-filled polypropylene: ductile cracking and impact behavior. J Polym Sci B Polym Phys 40:31–42
Varga J (1989) β-Modification of polypropylene and its two-component systems. J Therm Anal Calorim 35:1891–1912
Varga J, Karger-Kocsis J (1996) Rules of supermolecular structure formation in sheared isotactic polypropylene melts. J Polym Sci B Polym Phys 34:657–670
Huo H, Jiang SC, An LJ (2004) Influence of shear on crystallization behavior of the β phase in isotactic polypropylene with β-nucleating agent. Macromolecules 37:2478–2483
Chen YH, Mao YM, Li ZM, Hsiao BS (2010) Competitive growth of α- and β-crystals in β-nucleated isotactic polypropylene under shear flow. Macromolecules 43:6760–6771
Zhao YS, Su B, Zhong LC, Chen F, Fu Q (2014) Largely improved mechanical properties of a poly(styrene-b-isoprene-b-styrene) thermoplastic elastomer prepared under dynamic-packing injection molding. Ind Eng Chem Res 53(39):15287–15295
Wang GL, Zhou YG, Wang SJ, Chen JB, Zhang XL, Lu S (2013) Cylindritic structures of isotactic polypropylene molded by sequential co-injection molding. J Polym Res 20:212–223
Feng J, Wang L, Zhang RY, Wu JJ, Wang CY, Yang MB, Fu XR (2014) Formation of double skin-core orientated structure in injection-molded polyethylene parts: effects of ultra-high molecular weight polyethylene and temperature field. J Polym Res 21:432–446
Zhang ZC, Lei J, Chen YH, Chen J, Ji X, Tang JH, Li Z (2013) Tailored structure and properties of injection-molded atactic polypropylene/isotactic polypropylene. ACS Sustain Chem Eng 8:937–949
Lu QC, Dou Q (2017) Investigation on microstructures, melting and crystallization behaviors, mechanical and processing properties of β-isotactic polypropylene/CaCO3 toughening masterbatch composites. J Polym Res 24:206–221
Bao RY, Cao J, Liu ZY, Yang W, Xie BH, Yang MB (2014) Towards balanced strength and toughness improvement of isotactic polypropylene nanocomposites by surface functionalized graphene oxide. J Mater Chem A 2:3190–3199
Turner-Jones A, Aizlewood JM, Becketc DR (1964) Crystalline form of isotactic Polyprolylene. Makromol Chem 75:134–158
Fujiyama M, Wakino T, Kawasaki Y (1988) Structure of skin layer in injection-molded polypropylene. J Appl Polym Sci 35:29–49
Kantz MR, Newman HD, JR SFH (1972) The skin-Core morphology and structure property relationships in injection-molded polypropylene. J Appl Polym Sci 16:1249–1260
Yoshida T, Fujiwara Y, Asano T (1983) Plastic deformation of oriented lamellae: 3. Drawing behaviour of β-phase isotactic polypropylene. Polymer 24:925–929
Zhang CB, Liu GM, Song Y, Zhao Y, Wang DJ (2014) Structural evolution of β-iPP during uniaxial stretching studied by in-situ WAXS and SAXS. Polymer 55:6915–6923
Cai ZW, Zhang Y, Li JQ, Xue FF, Shang YR, He XH, Feng JC, Wu ZH, Jiang SC (2012) Real time synchrotron SAXS and WAXS investigations on temperature related deformation and transitions of β-iPP with uniaxial stretching. Polymer 53: 1593–1601
Acknowledgements
This work is supported by the National Natural Science Foundation of China Programs (11372284). The β nucleating agent was kindly supplied by Shanxi Provincial Institute of Chemical Industry, China.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Wang, G., Hou, S., Cao, J. et al. Reinforcing and toughening isotactic polypropylene through shear-induced crystallization and β-nucleating agent induced crystallization. J Polym Res 25, 233 (2018). https://doi.org/10.1007/s10965-018-1632-1
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10965-018-1632-1