The effect of hexamethylene diisocyanate modified ALCELL lignin as a coupling agent on the flexural properties of oil palm empty fruit bunch – polypropylene composites

ALCELL lignin has been employed as a coupling agent in oil palm empty fruit bunch (EFB)–polypropylene (PP) composites. The lignin has been chemically modified with hexamethylene diisocyanate (HMDI). Evidence for the reaction between HMDI and lignin has been observed by using Fourier transform infrared (FTIR) analysis. The effect of lignin as a coupling agent on the flexural properties has been studied. The results show that the HMDI‐modified lignin is able to impart greater compatibility between EFB and PP. This is reflected in the greater flexural strength shown by the composites with HMDI‐modified lignin than those with the unmodified lignin. Scanning electron microscopy studies show that HMDI‐modification of lignin results in a better blending and compatibility between lignin and PP matrix. The glass transition temperature of lignin increases as the level of HMDI modification is increased. © 2001 Society of Chemical Industry     

Oil Palm Empty Fruit Bunch ‐ Polypropylene Composites ‐ The Effect of Modified Alcell Lignin as a Compatibilizer on Tensile Properties

Abstract

ALCELL lignin has been employed as compatibilizer in the empty fruit bunch (EFB)-polypropylene (PP) composites. The lignin has been chemically modified with toluene diisocyanate (TDI) to various weight loadings. The effect of lignin as compatibilizer on the tensile properties has been studied. The results show that the TDI-modified lignin is able to impart greater compatibility between EFB and PP. This is reflected in the greater tensile properties shown by the composites with TDI-modified lignin than the ones with the unmodified lignin.     

Influence of grafted polypropylene on the mechanical properties of mineral‐filled polypropylene composites

The purpose of this work was to study how mineral fillers would behave in a polypropylene (PP) matrix when PP modified with maleic anhydride (MA) and/or itaconic acid (IA) was used as a coupling agent in the preparation of mineral‐filled PP composites. The composites were characterized with tensile mechanical measurements and morphological analysis. The optimum amount of the coupling agent to be used to obtain composites with improved mechanical properties was established. The results indicated that these coupling agents enhanced the tensile strength of the composites significantly, and the extent of the coupling effect depended on the nature of the interface that formed. The incorporation of coupling agents enhanced the resistance to deformation of the composite. The behavior of IA‐modified PP as a coupling agent was similar to that of a commercial MA‐modified PP for the filled PP composites. Evidence of improved interfacial bonding was revealed by scanning electron microscopy studies, which examined the surfaces of fractured tensile test specimens; their microstructures confirmed the mechanical results with respect to the observed homogeneous or optimized dispersion of the mineral‐filler phase in these composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2343–2350, 2007     

Influence of the coupling agent and graphene oxide on the thermal and mechanical behavior of tea dust–polypropylene composites

In this study, the effects of a coupling agent and additive on the physicomechanical (morphological, mechanical, thermal, and swelling) properties of tea dust (TD)–polypropylene (PP) composites were studied. TD–PP composites were prepared with untreated tea dust (UTD) and tetraethylsilane (TES)‐treated TD or silanated tea dust (STD) particles at ratios of 0:100, 10:90, 20:80, 30:70, and 40:60 w/w. Initially, TD particles were grafted by TES as a coupling agent, and these STD particles were then modified with graphene oxide (GO) as an additive to study their effects on the STD–PP composites; these were compared to the STD–PP and UTD–PP composites in accordance with a study of improvements in the mechanical properties. All of the TD–PP composites were analyzed with Fourier transform infrared spectroscopy, scanning electron microscopy, and mechanical, thermal, and physical tests. The thermal and mechanical properties of both the STD–PP and GO‐modified STD–PP composites were found to be improved as compared to those of the UTD–PP composites. So, the recycling of a large amount of TD as a waste material could be useful in the preparation of TD–PP composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42927.     

Comparative study of maleated polypropylene as a coupling agent for recycled low‐density polyethylene/wood flour composites

The effects of the type of coupling agent and virgin polypropylene (PP) content on the mechanical properties and water absorption behavior of recycled low‐density polyethylene/wood flour (WF) composites were investigated. The fractured surfaces of these recycled wood/plastic composites (rWPCs) were examined to gain insight into the distribution and dispersion of WF within the polymer matrix. The results indicate that the use of 100% recycled polymer led to inferior mechanical properties and to a greater degree of moisture absorption and swelling when compared to recycled polymer–virgin PP wood/plastic composites. This could have been related to the poor melt strength and inferior processability of the recycled polymer. The extent of improvement of the mechanical properties depended not only on the virgin PP content in the matrix but also on the presence of maleic anhydride (MA) modified PP as the coupling agent. Higher concentrations of MA group were beneficial; this improvement was attributed to increased chemical bonding (ester linkages) between hydroxyl moieties in WF and anhydride moieties in the coupling agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Water bamboo husk‐reinforced poly(butylene succinate) biodegradable composites

The water bamboo husk is one of major agricultural wastes in Taiwan. In this study, the fiber and powder obtained from the water bamboo husk were chemically modified by coupling agents. Furthermore, the modified fiber and powder were added to the biodegradable polymer poly(butylene succinate) (PBS) separately, to form novel fiber‐reinforced composites. Morphologies, mechanical properties, and heat resistance of these water bamboo husk‐reinforced composites were investigated. The results indicate that the fibers modified by coupling agents exhibited better compatibility with the polymer matrixes than did the untreated fibers. Moreover, it is found that the thermal properties were improved as plant fiber was incorporated to those polymers. Furthermore, the mechanical properties were also increased with the addition of coupling agent‐treated fiber. On the other hand, it is found that the homogeneity of untreated powder‐containing samples is better than that of untreated fiber‐containing samples. Moreover, the results reveal that the powders modified with coupling agents were not effective in improving the mechanical properties of the reinforced PBS. This is due to the bulky structure of lignin leading to a smaller reaction ratio with the coupling agents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 188–199, 2006     

Effect of clinoptilolite filler on the physical and mechanical properties of polypropylene

This study aims to investigate the mechanical and physical properties of polypropylene (PP) filled by natural zeolite. For this purpose, a natural zeolite (at 1–6 wt% filler loadings) with two different particle sizes was used. Two different kinds of silane coupling agents (3‐aminopropyltriethoxysilane, GAPTES and 3‐glycidoxypropyltrimethoxysilane, GPTMS) at three different volume ratios were used to improve the zeolite compatibility with PP and to improve the mechanical properties of composites. Fillers and PP were compounded with a twin screw extruder, and the composites were moulded with injection moulding press. The samples were subjected to mechanical tests (i.e., impact and tensile tests) and physical tests (i.e., hardness, density, and melt flow index, MFI). The physical test results showed that the levels of hardness and density of both unmodified and modified zeolite‐filled PP composites were higher compared with neat PP. The MFI values of composites were decreased by increasing zeolite loading level. Composites including GAPTES modified zeolite showed improved yield strength, impact strength and stiffness compared with composites filled with unmodified zeolite particles. POLYM. COMPOS. 34:1396–1403, 2013. © 2013 Society of Plastics Engineers     

Effect of a silane coupling agent on the properties of white rice husk ash–polypropylene/natural rubber composites

White rice husk ash (WRHA)–polypropylene (PP)/natural rubber (NR) composites were prepared using a Brabender Plasticorder at 180 °C and a rotor speed of 50 rev min^?1. The mechanical and water‐absorption properties were studied. The incorporation of WRHA into the PP/NR matrix has resulted in the improvement of the tensile modulus; however, the tensile strength, elongation at break and stress at yield decreased with increasing WRHA loading. Poor filler matrix interactions are believed to be responsible for the decrease in the properties. Incorporation of a silane coupling agent, 3‐aminopropyl triethoxysilane (3‐APE), improved tensile modulus, tensile strength and stress at yield of the composites. Water‐absorption studies indicate that the use of the coupling agent reduced the amount of water absorbed by the composites. © 2001 Society of Chemical Industry     

聚丙烯接枝马来酸酐对聚丙烯/凹凸棒石复合体系力学性能的影响

使用聚丙烯接枝马来酸酐(PP-g-MAH)对聚丙烯(PP)/凹凸棒石(AT)复合体系进行了增容,研究了PP-g-MAH对PP/原矿AT和PP/钛酸酯偶联剂改性AT复合体系力学性能的影响,观察了AT在PP中的分散状态以及PP/AT复合体系的断面形貌.结果表明P-g-MAH对AT在PP中分散状态没有明显影响;但加入5%的PP-g-MAH能够改善PP与原矿AT的相容性,提高PP/原矿AT复合体系的力学性能;加入PP-g-MAH对PP/钛酸酯偶联剂改性AT复合体系力学性能的改善不明显.     

Parameters regulating interfacial and mechanical properties of short glass fiber reinforced polypropylene

The performance of thermoplastic composites is known to depend on the intrinsic properties of the two composite components, the quality of the fiber–matrix interface, and the crystalline properties of their matrix. The objective of this work is to characterize the effect of the addition of modified polypropylene (PP) and silane coupling agent on the mechanical and interfacial properties of short fiber reinforced PP composites. Differential scanning calorimetry (DSC), single fiber composite fragmentation tests (SFC), and mechanical testing are used to understand the different parameters regulating the interfacial properties of composites. No influence of the modified PP on the level of crystallinity is observed. Some differences in the size of the spherulites are observed for acrylic acid grafted PP (PP‐g‐AA). Those samples also show lower mechanical properties in spite of good interfacial interactions. Maleic anhydride grafted PP (PP‐g‐MAh) leads to better mechanical performances than PP‐g‐AA. A high MAh content PP‐g‐MAh grade with low viscosity is the best polymeric additive used in the present work. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2047–2060, 2000     

Polypropylene–intumescent flame‐retardant composites based on meleated polypropylene as a coupling agent

The phosphoric acid‐pentaerythritol‐melamine copolymer, which is composed of three main components of intumescent flame retardant (IFR) and has optimal intumescent degree, was selected as IFR. The influence of meleated polypropylene (PP‐g‐MAH) on the properties and compatibility of IFR polypropylene (PP) composites were studied. The results obtained from mechanical tests, rheological behavior of composites, and scanning electron microscope showed that PP‐g‐MAH was a true coupling agent for IFR/PP blends and did not change the necessary flame retardancy. The cocrystallization between bulk PP and PP segments of PP‐g‐MAH was also proven by WAXD analysis. Flow test showed that the flow behaviors of composites in the melt are those of a pseudoplastic and it is very small for PP‐g‐MAH affecting rheological behavior of the PP/IFR composite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 257–262, 2002     

Lignin‐polystyrene composite foams through high internal phase emulsion polymerization

The composites made‐up from renewable fillers and polymer matrix have drawn great attention due to the renewable nature, improved thermal and mechanical properties, environmental issues and most importantly to reduce dependency on fossil fuel resources. In this work, kraft lignin in its modified form (butylated lignin) was used to make composites with polystyrene successfully through bulk polymerization and high internal phase emulsion (HIPE) polymerization. The kraft lignin was first modified to butyrated lignin by esterification using 1‐Methylimidazole as a catalyst in order to increase the compatibility as fillers with both monomer and polymer, which was further studied and verified through Hansen solubility parameter model. The thermal, mechanical, and structural properties of the lignin/polymer composites were systematically investigated. The incorporation of lignin in the composites could increase the modulus significantly and almost double (1,391 MPa) at 15 wt% of lignin loading as compared with bare composites. Excellent porous structure and mechanical properties are maintained with the lignin content as high as 10 wt% of the total foam mass. POLYM. ENG. SCI., 59:964–972, 2019. © 2018 Society of Plastics Engineers     

Ink‐eliminated waste paper sludge flour‐filled polypropylene composites with different coupling agent treatments

Ink‐eliminated sludge flour (IESF), waste residue from the recycling treatments of waste paper, was utilized as a new kind of filler to reinforce polypropylene (PP) in this research work. Different coupling agents, including maleated anhydride grafted PP (MAPP), stearic acid (SA), and titanate (NDZ‐101), were used to increase the compatibility between IESF and PP. By using different measurements, the microstructure, morphology, thermal behaviors, and mechanical properties of the IESF/PP composites were investigated in detail. It was found that IESF, as a nucleation agent, not only induced the crystallization orientation of PP but also accelerate the crystallization rate of PP. Just as indicated in the experiments, the presence of IESF has shown the advantages of increasing the dimensional stability, the hardness and the flexural property, and the presence of coupling agents has a favorable effect on the improvement of dimensional stability. Moreover, the coupling agent has minor influence on the mechanical property, even causes some decrease in the impact strength. Among these three coupling agents, MAPP is found to be the best coupling agent for increasing the interfacial adhesion between IESF and PP, and the MAPP addition makes the PP composite possess the quickest crystallization rate and greatest tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 513–520, 2003     

Effects of silane coupling agent and maleic anhydride‐grafted polypropylene on the morphology and viscoelastic properties of polypropylene–mica composites

In this study, morphology, and dynamic and mechanical properties of polypropylene–mica (PP–Mica) composites were investigated. To enhance the adhesion between PP and mica, maleic anhydride‐grafted PP (MAPP) and treated mica with silane coupling agent were used. MAPP (as a compatibilizer) and silane coupling agent (as a filler surface modifier) caused an interfacial bonding in the mica filled polypropylene composites. The effect of mica content, MAPP, and treated mica with silane coupling agent on the morphological properties were investigated by Scanning Electron Microscopy (SEM). The results showed that with increasing MAPP or silane coupling agent, dispersion of filler and adhesion between PP and filler were improved. Mechanical data showed that with increasing MAPP and mica treated with silane coupling agent, tensile modulus and flextural strength of composites were enhanced. Dynamic rheological behavior of composites was also investigated within the domain of linear viscoelasticity. The rheological observations indicated that the complex viscosity, storage and loss moduli increased, and tan δ decreased with increasing mica content. POLYM. COMPOS. 27:491–496, 2006. © 2006 Society of Plastics Engineers.     

Compatibilization of intumescent flame retardant/polypropylene composites based on α‐methacrylic acid grafted polypropylene

A phosphoric acid–pentaerythritol–melamine copolymer was selected as an intumescent flame retardant (IFR). The influence of α‐methacrylic acid grafted polypropylene (PP‐g‐MAA) on the properties and compatibility of IFR/PP composites was studied. The results obtained from mechanical tests and scanning electron microscopy showed that PP‐g‐MAA was a true coupling agent for IFR/PP blends, but it did not change the necessary flame retardancy. The cocrystallization between bulk PP and PP segments of PP‐g‐MAA was proved by wide‐angle X‐ray diffraction analysis. A flow test showed that the flow behaviors of composites in the melt were those of a pseudoplastic liquid and it was very small for PP‐g‐MAA and affected the rheological behavior of the PP/IFR composite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3128–3132, 2002; DOI 10.1002/app.10099     

正辛醇接枝改性杉木粉的制备及其对PPI杉木粉复合材料性能的影响

以甲苯二异氰酸酯（TDI）为偶联剂将正辛醇接枝到杉木粉表面,同时考察处理前后杉木粉填充PP复合材料的力学性能。通过红外光谱分析（FTIR）,扫描电子显微镜分析（SEM）等方法对材料的结构进行了分析。结果表明：与未接枝改性杉木粉相比接枝改性杉木粉/PP复合材料的力学性能显著提高,其拉伸强度和冲击强度可分别提高44．3％和65.0％。扫描电镜照片显示正辛醇接枝改性杉木粉在基体中分散更均匀。     

Influence of polyamide 6 as a charring agent on the flame retardancy,thermal, and mechanical properties of polypropylene composites

In this work, polyamide 6 (PA6) as a charring agent has been used in combination with thermoplastic polyurethane (TPU)‐microencapsulated ammonium polyphosphate (MTAPP) forming intumescent flame retardants (IFRs) which applies in polypropylene (PP). The effects of the IFRs on the flame retardancy, morphology of char layers, water resistance, thermal properties and mechanical properties of flame‐retardant PP composites are investigated by limiting oxygen index (LOI), UL‐94 test, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mechanical properties test. The results show that the PP/MTAPP/PA6 composites exhibit much better flame‐retardant performances than the PP/MTAPP composites. The higher LOI values and UL‐94 V‐2 of the PP/MTAPP composites with suitable amount of PA6 are obtained, which is attributed to the thick and compact char layer structure evidenced by SEM. The results from TGA and DSC demonstrate that the introduction of PA6 into PP/MTAPP composites has a great effect on the thermal stability and crystallization behaviors of the composites. Furthermore, the mechanical properties of PP/MTAPP/PA6 composites are also improved greatly due to the presence of PA6 as a charring agent. POLYM. ENG. SCI., 55:1355–1360, 2015. © 2015 Society of Plastics Engineers     

Effect of a macromolecular coupling agent on the properties of aluminum hydroxide/PP composites

Polypropylene (PP)/aluminum hydroxide (ATH) composites were prepared in a melt mixer with addition of polypropylene functionalized with vinyltriethoxysilane (VTES) as a coupling agent. The effects of ATH and PP‐VTES on the melt flow indices (MFI), tensile properties, decomposition temperatures, and flame retardancy of composites were analyzed. It was verified that increased ATH concentration reduced MFI and tensile properties, but increased the decomposition temperature under oxidative atmosphere and improved the flammability properties. Addition of PP modified with VTES slightly improved tensile strength and maximum elongation and granted the best results for the flammability tests of the materials showing that it can be an effective coupling agent for PP/ATH composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1799–1805, 2006     

Hydrophobic coating of mica by piranha solution activation,silanization grafting,and copolymerization with acrylate monomers

Hydrophobic mica particles were prepared by piranha solution activation, silanization, and copolymerization with acrylate monomers. Its surface morphology, hydrophilic properties, and thermogravimetric analysis changed differently in comparison with those of pristine mica. Scanning electron microscopy (SEM) showed that the modified (001) mica surface changed from flat to coarse. Thermogravimetric curves demonstrated that silane coupling agents and the grafted polymer were anchored on the modified‐mica surface. The alternating surface polarity state was verified by different dispersion performances in the solvents. SEM images showed that the polypropylene (PP)/modified‐mica composites had a better quality compatibility than the PP/untreated‐mica composites. The PP/polymer‐grafted‐mica composites had improved mechanical properties, including stretching, tension, and impact properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44985.     

Unidirectional hemp and flax EP‐ and PP‐composites: Influence of defined fiber treatments

In some technical areas, mainly in the automotive industry, glass fiber reinforced polymers are intended to be replaced by natural fiber reinforced polymer systems. Therefore, higher requirements will be imposed to the physical fiber properties, fiber‐matrix adhesion, and the quality assurance. To improve the properties of epoxy resins (EP) and polypropylene (PP) composites, flax and hemp fibers were modified by mercerization and MAH‐PP coupling agent was used for preparing the PP composites. The effects of different mercerization parameters such as concentration of alkali (NaOH), temperature, and duration time along with tensile stress applied to the fibers on the structure and properties of hemp fibers were studied and judged via the cellulose I–II lattice conversion. It was observed that the mechanical properties of the fibers can be controlled in a broad range by using appropriate mercerization parameters. Unidirectional EP composites were manufactured by the filament winding technique; at the PP matrix material, a combination with a film‐stacking technique was used. The influence of mercerization parameters on the properties of EP composites was studied with hemp yarn as an example. Different macromechanical effects are shown at hemp‐ and flax‐PP model composites with mercerized, MAH‐PP‐treated, or MAH‐PP‐treated mercerized yarns. The composites' properties were verified by tensile and flexural tests. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2150–2156, 2004