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Influence of Branch Content on the Mechanical Properties of metallocene LLDPEs Ashraful Islam, Ibnelwaleed A. Hussein Department of Chemical Engineering.

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Presentation on theme: "Influence of Branch Content on the Mechanical Properties of metallocene LLDPEs Ashraful Islam, Ibnelwaleed A. Hussein Department of Chemical Engineering."— Presentation transcript:

1 Influence of Branch Content on the Mechanical Properties of metallocene LLDPEs Ashraful Islam, Ibnelwaleed A. Hussein Department of Chemical Engineering PPS 21 st Annual Meeting, Leipzig, Germany June 19-23, 2005

2 Introduction Introduction Literature Review Literature Review Objectives Objectives Experimental work Experimental work Results & Discussions Results & Discussions OUTLINE

3 HDPELDPE m-LLDPE Schematic representation of the different classes of PE ZN-LLDPE

4 Morphology of polyethylene

5 LITERATURE REVIEW Authors [Year] Comments Mandelkern & Maxfield [1979] Studied the morphology of ZN LDPEs for two different extreme crystallization modes. The thermodynamic properties of LDPE primarily governed by BC and not much dependent on molecular weight. Popli & Mandelkern [1987] Studied mechanical properties of HDPE & LDPEs. LDPEs showed lower yield stress compared to HDPEs. A nonlinear relationship was found for Young’s modulus as function of BC for ZN-LDPEs. Ultimate properties were not strongly influenced by BC.

6 Authors [Year] Comments Bensason et al. [1996] Classified Ethylene-Octene copolymers based on BC. LITERATURE REVIEW (Cont’d)

7 Authors [Year] Comments Simanke et al [1999] Reported low strain properties of m-LLDPEs. They failed to report high strain properties due to the sample slippage in the grips. Walker et al [2003] DSC analysis of m-LLDPEs showed a progressive increase in T m with decreasing BC. The results also showed that the ZN-LLDPEs have higher melting temperature than the m-LLDPEs.

8 LITERATURE REVIEW (Cont’d) Summary: 1.Studied thermal and mechanical properties of different catagories of ZN HDPE, LDPE and LLDPEs. 2.Investigated the effect of Mw and thermal treatment on the various thermal transitions. 3.Examined the effect of comonomer type and BC on the different thermal transitions of ZN-LLDPEs. 4.Compared the final properties of traditional ZN-LLDPE with m-LLDPE. 5.Studied the influence of BC on low strain properties of m-LLDPEs with BC less than 20 CH3/1000C.

9 Table 01: Polymer Characterization Resins Density, g/cm 3 M w, Kg/mol MI, g/10min MWD BC (CH 3 /1000C) m-EH120.918942.51.40 12.02 m-EH150.9121021.202.14 14.5 m-EH180.9001081.201.83 18.02 m-EH200.902952.02.06 19.74 m-EH240.895922.201.85 32.60 m-EH320.883972.202.02 32.17 ZN-EH170.917802.808.40 16.71

10 Resin Carver Press Thin Sheet Pneumatic Punch CutterDog-bone Instron Machine Experimental Steps (Mechanical)

11 Resin Aluminum Pans Press Modulated DSC LNCS Experimental Steps (Thermal)

12 Figure 03: Stress/Strain curves for EH m-LLDPEs with different BCs.

13 Table 2: Selected thermal properties of ethylene/  -olefins copolymers Resin BC (CH 3 /1000C) Melting Peak ( o C) DSC Crystallinity Values (%) BeforeAfterBeforeAfter m-EH12 12.02115.2114.740.341.6 m-EH15 14.50105.7103.034.936.0 m-EH18 18.0295.799.628.929.0 m-EH20 19.7445.1, 88.345.4, 94.731.131.5 m-EH24 23.6047.2, 90.343.2, 92.628.429.6 m-EH32 32.1746.4, 73.244.7, 80.022.625.2

14 Figure 04: Avrami plot for EH m-LLDPEs (Strain rate 4.92 min-1) Resinsm-EH12m-EH15m-EH18m-EH20m-EH24m-EH32 Avrami Exponent (n)0.651.341.311.441.351.34 Crystallization Rate Constant (k) 1.010.950.910.960.890.81

15 Figure 05: Yield Phenomena at crosshead speed of 125 mm/min

16 Figure 06: Young’s modulus as a function of BC (crosshead speed 125 mm/min)

17 Figure 07: Elongation at break as function of BC (crosshead speed 125 mm/min)

18 Figure 08: Ultimate tensile strength as function of BC (crosshead speed 125 mm/min).

19 Acknowledgements: Acknowledgements: King Abdul Aziz City for Science and Technology (KACST) for financial support KFUPM ExxonMobil, Belgium for providing free samples

20 Thanks


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