Rheological and Mechanical Properties of Wood-Based EPDM/PP Composites
Supervisor:guo ming hui
The research on the utilization of wood-based residues mainly focuses on two aspects:wood residues and paper-making waste liquor.Because wood residues have more properties of wood,so they are used in wide range.The research on the utilization of paper-making waste liquor mainly focuses on the extraction and modification of lignin.In this study,ammonium lignosulfonate(AL)was extracted from waste liquor of papermaking as the main material,combining ethylene propylene diene monomer(EPDM)and polypropylene(PP)to produce a new wood-based EPDM/PP composite with dynamic vulcanization process.And the effects of various factors on the properties of the composite were discussed.In this paper,the new material were made with the fixed amount of EPDM and variable amount for AL and PP.The effects of the amount of main materials on the properties of wood-based EPDM/PP composites were discussed.The effects of the amount of vulcanizing agent,accelerator,extrusion temperature and rotor rate on the properties of wood-based EPDM/PP composites under three curing systems of peroxide(DCP),sulfur(S)and phenolic resin(Sp1045)were studied.The reinforcement of wood flour and the effect of naphthene oil on the internal dispersion of the material were also studied The main conclusions of this paper are summarized as follows:(1)The performance of the composites caused by different input of main material.AL was served as the reinforcing fillers in the mixture system.With the increase of AL input from 50 to 100,the performance of mechanical strength,elastic modulus,storage modulus,loss modulus and complex viscosity of the composites increased obviously.With the increasing of A1 input from 100 to 150,the performance of mechanic strength,the storage modulus,loss modulus,and storage modulus hadn’t big change.At the same time,the tensile strength was reduced,and the modulus of elasticity was improved distinct.The crystallinity of the composite increased with the increase of the amount of PP,and decreased with the increase of the AL content.While the elasticity and viscosity of composites increased and the strength decreased with the increase of EPDM content.As a plastic phase,PP existed in the mixing system and with the increase of PP content,the elasticity and viscosity of composites increased,the strength of composites decreased,and the rubber characteristics became more and more obvious.With the increase of the PP dosage,the elasticity and viscosity of the composites decrease,the strength and crystallinity increase,and the plastic characteristics become more and more obvious.(2)The performance of the composites caused by different extrusion technologyThe extrusion technology in this paper included two parameters which were extrusion temperature and extrusion speed.The research showed that the change of the performance of the composite was the same with the increase of the extrusion temperature under the three difference vulcanization systems.The mechanic performances were the best under extrusion temperature on 180℃.But the storage modulus,loss modulus and complex viscosity decreased with the increase of the extrusion temperature.And the extrusion temperature hadn’t obviously impact on the crystallinity.Comparing to extrusion temperature,the extrusion speed had different influence on mechanical properties of the composites under the three different vulcanization systems.The extrusion speed in 100r/min led to the best mechanical performance under DCP vulcanization system.The extrusion speed in 150r/min led to the best mechanical properties base on Sulfur vulcanization.The extrusion speed in 50r/min led to the best mechanical performance base on phenolic resin vulcanization.Under DCP and Sulfur vulcanization systems,storage modulus,loss modulus,and complex viscosity was enhanced with the increase of extrusion speed.But under phenolic resin vulcanization,the modulus and viscosity were decreased firstly and then increased with the increase of extrusion speed.They were on the highest limit once extrusion speed was 150r/min.Regarding the crystallinity,it was reduced with the increase of extrusion speed under all the three vulcanization systems.(3)The performance of the composites caused by different amount of vulcanizing agents and accelerators.The study showed the mechanical properties can be the best base on the following parameters:DCP with 2,TAIC with 1.5,S with 2,TBSI with 2,PR with 12,Sncl2 with 2.Under DCP vulcanization system,the storage modulus,loss modulus,and complex viscosity decreased firstly and then increased caused by the increasing of DCP amount.They were on the lowest limit once DCP is 3 and on the highest limit once DCP is 4.Still under DCP vulcanization system,the storage modulus,loss modulus,and complex viscosity increased caused by the increasing of TAIC amount.They were on the lowest limit once TAIC is 0.5 and on highest limit once TAIC is 1.5.Under Sulfur and phenolic resin vulcanization systems,vulcanizing agents and accelerators hadn’t significant influence on the rheological property of the composites.The amount of vulcanizing agents and accelerators hadn’t obviously influence on crystallinity under these three vulcanization systems.(4)The investigation between different vulcanization systemsThe mechanical properties of the composites were the best under phenolic resin vulcanization system and the worse under peroxide vulcanization system and the worst under sulfur vulcanization system.But the difference between them was not significant.The storage modulus,loss modulus and complex viscosity of the composites were the best under peroxide vulcanization system,and the worse under sulfur vulcanization system,and the worst under phenolic resin vulcanization system.Among the data,viscosity and modulus had significant difference between peroxide vulcanization system and the other two vulcanization systems.The crystallinity of composites hadn’t big difference between these three vulcanization systems.But it was the highest under sulfur vulcanization system and lower under peroxide vulcanization system,and the lowest under phenolic resin vulcanization system.(5)The investigation on the reinforcement mechanism of wood flourThe results show that the amount of wood flour has a significant effect on the properties of composites.The mechanical properties of composites increased firstly with the increase of wood flour content,and it reach the maximum when wood flour content is 60 phr,and then decrease when wood flour content is 90 phr.The storage modulus,loss modulus and complex viscosity of composites increase with the increase of wood flour content.The crystallinity of composites is not significantly affected by wood flour content.(6)The performance of the composites caused by naphthenic oil on the dispersibility of the materialThe study exhibited that the performance of the composites were influenced significant by naphthenic oil.With the increasing of naphthenic oil amount,the viscosity of the mixed system getting worse.The performances including mechanical properties,storage modulus,loss modulus,complex viscosity and crystallinity were decreased once the amount of naphthenic oil increasing.When the amount of naphthene oil is 10 phr,the rubber particles are the smallest and the internal dispersion performance is the best.When the amount of naphthene oil is increased to 20 phr,the rubber particles begin to increase and disperse unevenly.When the amount of naphthene oil is 30 phr,the rubber particles continue to increase and disperse more unevenly.