Poor interfacial adhesion between biobased thermoplastics and natural fibers is recognized as a major drawback for biocomposites.To be applicable for the large-scale production,a simple method to handle is of importan...Poor interfacial adhesion between biobased thermoplastics and natural fibers is recognized as a major drawback for biocomposites.To be applicable for the large-scale production,a simple method to handle is of importance.This work presented poly(lactic acid)(PLA)reinforced with short-fiber and three reactive agents including anhydride and epoxide groups were selected as compatibilizers.Biocomposites were prepared by one-step meltmixing methods.The influence of reactive agents on mechanical,dynamic mechanical properties and morphology of PLA biocomposites were investigated.Tensile strength and storage modulus of PLA biocomposites incorporated with epoxide-based reactive agent was increased 13.9%and 37.4%compared to non-compatibilized PLA biocomposite,which was higher than adding anhydride-based reactive agent.SEM micrographs and Molau test exhibited an improvement of interfacial fiber-matrix adhesion in the PLA biocomposites incorporated with epoxide-based reactive agent.FTIR revealed the chemical reaction between the fiber and PLA with the presence of epoxide-based reactive agents.展开更多
This paper is about the use of power law model to fit experimental creep data of PP reinforced with calcium carbonate nanofiller at 10% optimum volume fraction with a view to characterizing the new material (PPC2) par...This paper is about the use of power law model to fit experimental creep data of PP reinforced with calcium carbonate nanofiller at 10% optimum volume fraction with a view to characterizing the new material (PPC2) parametrically. The creep parameters were evaluated for neat (PPC0) and reinforced PP (PPC2) to establish the influence of reinforcement on the creep variables like creep rate and creep activation energy. The coefficient parameter A estimated within the stress level range 13.08MPa-22.88MPa has the range 0.0165-0.0651 while the exponent parameter n has 0.299-0.370. The creep stress coefficient K and exponent m has the respective values 161.495 and 0.3288 for PPC0 and 1881.4965 and 0.5448 for PPC2. The value of the parameter p similar to Larson-Miller has the value 4014.1871. Two creep function models used found that PPC0 has higher activation energy with value 9.3642E-20 J/mol for the stress 13.08MPa and PPC2 has values for the stresses 13.08MPa, 19.61MPa and 22.88MPa as 5.55998E- 20J/mol,5.4573E-20J/mol and 4.845E-20J/mol respectively. Of the two master curves produced, that following Larson-Miller parameter is recommended as the relationship between lnσ and parameter f(σ) is relatively linear and will give better results than the curve assumed to follow Sherby-Dorn that will give average result.展开更多
The integration of implants or medical devices into the body tissues requires of good cell–material interactions.However,most polymeric materials used for these applications lack on biological cues,which enhanced mid...The integration of implants or medical devices into the body tissues requires of good cell–material interactions.However,most polymeric materials used for these applications lack on biological cues,which enhanced mid-and long-term implant failure due to weak integration with the surrounding tissue.Commonly used strategies for tissue–material integration focus on functionalization of the material surface by means of natural proteins or short peptides.However,the use of these biomolecules involves major drawbacks such as immunogenic problems and oversimplification of the constructs.Here,designed elastin-like recombinamers(ELRs)are used to enhance poly(methyl methacrylate)surface properties and compared against the use of short peptides.In this study,cell response has been analysed for different functionalization conditions in the presence and absence of a competing protein,which interferes on surface–cell interaction by unspecific adsorption on the interface.The study has shown that ELRs can induce higher rates of cell attachment and stronger cell anchorages than short peptides,being a better choice for surface functionalization.展开更多
Biogas production was investigated in this study as an alternative to wood as fuel using slurries of cow dung(T1),jatropha fruit exocarp(T2),cattle dung and jatropha fruit exocarp(T3)and cow dung,jatropha fruit exocar...Biogas production was investigated in this study as an alternative to wood as fuel using slurries of cow dung(T1),jatropha fruit exocarp(T2),cattle dung and jatropha fruit exocarp(T3)and cow dung,jatropha fruit exocarp with 10 g of iron filings(T4).The 1000 mL of slurry which included 50 mL of inoculum that compensated for the dead or weak micro-organism was made for each sample.At the end of five weeks,the volume of biogas collected from the samples T1,T2,T3,and T4 when added up,gave 77,154,145 and 586 mL,respectively.The sample mixture of cow dung,jatropha fruit exocarp,and iron filings(T4),gave the highest yield of biogas production with an average weekly production of 59 mL/kg for four weeks and on the fifth week about six times emission of biogas was obtained.The production rate of the biogas was rapid after the gestation period and the T4 emerged as the most substantial emission of all the samples producing 350 mL/kg on the fifth week.展开更多
The effect of niobium addition on the microstructure of cast AISI H13 hot work tool steel was evaluated by using EDX analyzer attached to the scanning electron microscope. The volume percent of eutectic area and eutec...The effect of niobium addition on the microstructure of cast AISI H13 hot work tool steel was evaluated by using EDX analyzer attached to the scanning electron microscope. The volume percent of eutectic area and eutectic cell size and also volume percent of different carbides of new steel, which is heat treated under different conditions, are also determined. The results show that the a niobium addition modifies the cast structure of Nb-alloyed hot work tool steel, and reduces the size and volume of eutectic cells, and increases the maximum hardness of the steel.展开更多
文摘Poor interfacial adhesion between biobased thermoplastics and natural fibers is recognized as a major drawback for biocomposites.To be applicable for the large-scale production,a simple method to handle is of importance.This work presented poly(lactic acid)(PLA)reinforced with short-fiber and three reactive agents including anhydride and epoxide groups were selected as compatibilizers.Biocomposites were prepared by one-step meltmixing methods.The influence of reactive agents on mechanical,dynamic mechanical properties and morphology of PLA biocomposites were investigated.Tensile strength and storage modulus of PLA biocomposites incorporated with epoxide-based reactive agent was increased 13.9%and 37.4%compared to non-compatibilized PLA biocomposite,which was higher than adding anhydride-based reactive agent.SEM micrographs and Molau test exhibited an improvement of interfacial fiber-matrix adhesion in the PLA biocomposites incorporated with epoxide-based reactive agent.FTIR revealed the chemical reaction between the fiber and PLA with the presence of epoxide-based reactive agents.
文摘This paper is about the use of power law model to fit experimental creep data of PP reinforced with calcium carbonate nanofiller at 10% optimum volume fraction with a view to characterizing the new material (PPC2) parametrically. The creep parameters were evaluated for neat (PPC0) and reinforced PP (PPC2) to establish the influence of reinforcement on the creep variables like creep rate and creep activation energy. The coefficient parameter A estimated within the stress level range 13.08MPa-22.88MPa has the range 0.0165-0.0651 while the exponent parameter n has 0.299-0.370. The creep stress coefficient K and exponent m has the respective values 161.495 and 0.3288 for PPC0 and 1881.4965 and 0.5448 for PPC2. The value of the parameter p similar to Larson-Miller has the value 4014.1871. Two creep function models used found that PPC0 has higher activation energy with value 9.3642E-20 J/mol for the stress 13.08MPa and PPC2 has values for the stresses 13.08MPa, 19.61MPa and 22.88MPa as 5.55998E- 20J/mol,5.4573E-20J/mol and 4.845E-20J/mol respectively. Of the two master curves produced, that following Larson-Miller parameter is recommended as the relationship between lnσ and parameter f(σ) is relatively linear and will give better results than the curve assumed to follow Sherby-Dorn that will give average result.
基金This work was supported by the Spain’s Ministerio de Economı´a y Competitividad[projects MAT2008-06887-C03-01,MAT2010-15310,MAT2013-41723-R,MAT2013-42473-R,VA313U14 and VA244U13].X.P.acknowledges grant BES-2009-027524 from the Spain’s Ministerio de Economı´a y Competitividad.
文摘The integration of implants or medical devices into the body tissues requires of good cell–material interactions.However,most polymeric materials used for these applications lack on biological cues,which enhanced mid-and long-term implant failure due to weak integration with the surrounding tissue.Commonly used strategies for tissue–material integration focus on functionalization of the material surface by means of natural proteins or short peptides.However,the use of these biomolecules involves major drawbacks such as immunogenic problems and oversimplification of the constructs.Here,designed elastin-like recombinamers(ELRs)are used to enhance poly(methyl methacrylate)surface properties and compared against the use of short peptides.In this study,cell response has been analysed for different functionalization conditions in the presence and absence of a competing protein,which interferes on surface–cell interaction by unspecific adsorption on the interface.The study has shown that ELRs can induce higher rates of cell attachment and stronger cell anchorages than short peptides,being a better choice for surface functionalization.
文摘Biogas production was investigated in this study as an alternative to wood as fuel using slurries of cow dung(T1),jatropha fruit exocarp(T2),cattle dung and jatropha fruit exocarp(T3)and cow dung,jatropha fruit exocarp with 10 g of iron filings(T4).The 1000 mL of slurry which included 50 mL of inoculum that compensated for the dead or weak micro-organism was made for each sample.At the end of five weeks,the volume of biogas collected from the samples T1,T2,T3,and T4 when added up,gave 77,154,145 and 586 mL,respectively.The sample mixture of cow dung,jatropha fruit exocarp,and iron filings(T4),gave the highest yield of biogas production with an average weekly production of 59 mL/kg for four weeks and on the fifth week about six times emission of biogas was obtained.The production rate of the biogas was rapid after the gestation period and the T4 emerged as the most substantial emission of all the samples producing 350 mL/kg on the fifth week.
文摘The effect of niobium addition on the microstructure of cast AISI H13 hot work tool steel was evaluated by using EDX analyzer attached to the scanning electron microscope. The volume percent of eutectic area and eutectic cell size and also volume percent of different carbides of new steel, which is heat treated under different conditions, are also determined. The results show that the a niobium addition modifies the cast structure of Nb-alloyed hot work tool steel, and reduces the size and volume of eutectic cells, and increases the maximum hardness of the steel.
