Study On Performance Of Tetra Pak-based Electromagnetic Shielding Composites

Tetra Pak/HDPE electromagnetic shielding composites were prepared with Tetra Pak waste,high density polyethylene (HDPE), maleic anhydride-grafted-polyethlene (MAPE), ionomer andaddition agents. First, an optimized formula was obtained using Box-Behnken design ofexperiments in conjunction with response surface methodology, and the responses were flexuralmodulus and flexural strain at break. Second, Tetra Pak/HDPE/metal particle electromagneticshielding composite was prepared with Tetra Pak waste, HDPE, coupling agent-processed400mesh metal particles (copper, nickle, iron). The effect of metal kind, filling volume, couplingagent kind, concentration of coupling agent and different processings on the composite wasstudied. At last, Tetra Pak/HDPE/copper mesh electromagnetic shielding composite was preparedwith different copper mesh and the optimized formula. The effect of copper mesh, copper layers,distance between layers and angle between layers on mechanical properties and electromagneticshielding effectiveness of composites was also studied in this paper. The main conclusions are asfollows:(1) The quadratic equation of flexural modulus (E f) can be modeled asY1=-795.81090+155.72659′A-18.18912′B+16.68480′C-1.23983′AB-0.48878′AC+10.4444′BC-2.51650′A2-3.08591′B2-7.96357′C2using Box-Behnken design composed of threefactors, A-HDPE, B-MAPE and C-Ionomer. The model P-value of0.0478(<0.05) indicates thatmodel is significant. The lack of fit P-value of0.3565(>0.05) is insignificant. The order ofpriority for higherE fis B-MAPE>C-Ionomer> A-HDPE.(2) The quadratic equation of flexural strain at break (e fB) can be modeled asY2=3.79584-0.0632′A-0.62587′B+0.2703′C+0.029611′AB-7.61111′10-3′AC+0.022716′BC+9.5′10-5′A2-0.013728′B2+8.74074′10-3′C2using Box-Behnken design composed ofthree factors, A-HDPE, B-MAPE and C-Ionomer. The model P-value of0.0396(<0.05) indicatesthat model is significant. The lack of fit P-value of0.5860(>0.05) is insignificant. The order ofpriority for highere fBis C-Ionomer> B-MAPE> A-HDPE.(3)The optimization of multi-response was as follows: HDPE of30.62%, MAPE of6.35%and Ionomer of6.37%when the weight ofEf ande fBwas1:1. Under these conditions, thepredictedE fande fBwere1242.23MPa and4.70%.(4)The addition of10%(vol) metal particle (copper, nickle, iron) direct-processed by1.0%silane coupling agent (KH550) into Tetra Pak/HDPE composites made a contribution to flexuralmodulus and flexural strength. Tetra Pak/HDPE/copper particle composite showed bestelectromagnetic shilding effectiveness (SE) as a whole at frequency range of9kHz~1.5GHz. (5)Direct-processing was proved more suitable than wet-processing to improve mechanicalproperties for the composites, no matter silane (KH550) or titanate (NDZ401) coupling agentunder the same concentration. The mechanical properties of composites processed by KH550were higher than that of NDZ401by the same processing.When copper particles were treated by2.0%KH550, the flexural modulus and flexural strength of Tetra Pak/HDPE/copper particlecomposites were2850MPa and59.53MPa.(6)The coupling mechanism of KH550revealed that, the hydrolyzed ethoxy groups ofKH550reacted with the hydroxyl groups of Cu surface, and–NH2of KH550remained free toform the hydrogen bond. The isopropoxy groups of NDZ401also hydrolyzed completely insolution, and reacted with the hydroxyl groups of Cu surface. The long carbon chain group ofNDZ401may twine physically or react chemically with PE in the matrix.(7)The flexural modulus and flexural strength of Tetra Pak/HDPE/metal particle compositesrised with the increase of filling volume (0~20%), and thickness swelling and water absorptionrate of24h showed the opposite trend. Nevertheless, the SE of Tetra Pak/HDPE/metal particlecomposites was unsatisfactory (<10dB) for the reason that, copper particles were wrapped by PEor insulated CuO, with few conductive path formed.(8)The flexural modulus and flexural strength of Tetra Pak/HDPE/copper mesh compositeshad a relationship with aperture ratio of copper mesh. Higher aperture ratio of copper mesh ledhigher flexural modulus and flexural strength. The SE of Tetra Pak/HDPE/copper meshcomposites was significantly raised than that of Tetra Pak/HDPE composites by over20dB, and itrised with the increase of mesh number. When more copper meshes were added (1~4layers), theSE of these composites became higher, and the increase became smaller.(9) The flexural modulus and flexural strength of Tetra Pak/HDPE/copper mesh compositesdecreased with the distance (1mm~4mm) between two copper mesh layers, and the SE of thecomposites declined at high frequency. When two copper mesh layers got a distance of1mm, thecomposite showed good electromagnetic shielding effectiveness of50dB in the range offrequency tested.(10) The flexural modulus and flexural strength of Tetra Pak/HDPE/copper meshcomposites increased with the angle (0°~45°) between two copper mesh layers. The SE of thecomposite with an angle of45°was higher than that of the composites with angle of0°and22.5°in the frequency range of100MHz~660MHz. The order of SE for different angle isSE0°>SE45°>SE22.5°in the frequency range of660MHz~1.5GHz.