Three-stage interaction of dimethyl phthalate,dibutyl phthalate,and poly(vinyl acetate) with poly(methyl methacrylate)

The interaction of dimethyl phthalate (DMP), n-dibutyl phthalate (DBP), and poly(vinyl acetate) (PVAc) with poly(methyl methacrylate) (PMMA) was studied. Changes in the tensile strength, elastic modulus, and percentage elongation at break of the PMMA-additive films produced were followed using the Instron testing machine. The three additives produced (1) an initial plasticization, with a decrease in tensile strength and modulus and a possible increase in elongation; (2) an antiplasticization, with accompanying increase in tensile strength and modulus and an anomalous increase in elongation; and (3) a final plasticization, with a marked decrease in tensile strength and modulus and a definite increase in elongation of PMMA. The three effects were influenced by the molecular weight of the PMMA. A spacer effect by the interposition of the molecules of the additives between those of PMMA is proposed for the initial plasticization, while for the final plasticization, a lubrication action of the plasticizers on PMMA is suggested. Antiplasticization is explained by the formation of secondary bonds between the antiplasticizer and the PMMA molecules.     

Mechanical and barrier properties of polyvinyl chloride plasticized with dioctyl phthalate,epoxidized soybean oil,and epoxidized cardanol

Plasticized polyvinyl chloride (PVC) films were prepared by melt compounding and compression molding using epoxidized cardanol (EC), a biobased plasticizer and its plasticization effect was compared with epoxidized soybean oil (ESBO) and dioctyl phthalate (DOP). The mechanical, migration, thermal, and barrier properties of the plasticized films were compared. The effect of replacing DOP with EC on the properties of PVC films was also investigated. The tensile strength, elongation at break, tensile modulus and impact strength values of PVC/EC films were higher in comparison to PVC/DOP and PVC/ESBO films at a fixed plasticizer loading of 40 wt.%. Also, the films prepared with a mixture of DOP + EC showed higher tensile strength and elongation at break compared to that of films prepared with only DOP. The PVC/EC films showed good thermal stability and reduced oxygen transmission rate (OTR) compared to PVC/DOP films. The addition of graphene and nanoclay in the PVC/plasticizer system exhibited an increase in oxygen transmission. However, the oxygen barrier property of nano filler incorporated PVC/EC films was better than PVC/DOP films. All the films showed negligible water vapor transmission rate (WVTR).     

Thermal and mechanical properties of plasticized poly(L‐lactic acid)

Acetyl tri‐n‐butyl citrate (ATBC) and poly(ethyleneglycol)s (PEGs) with different molecular weights (from 400 to 10000) were used in this study to plasticize poly(L‐lactic acid) (PLA). The thermal and mechanical properties of the plasticized polymer are reported. Both ATBC and PEG are effective in lowering the glass transition (T_g) of PLA up to a given concentration, where the plasticizer reaches its solubility limit in the polymer (50 wt % in the case of ATBC; 15–30 wt %, depending on molecular weight, in the case of PEG). The range of applicability of PEGs as PLA plasticizers is given in terms of PEG molecular weight and concentration. The mechanical properties of plasticized PLA change with increasing plasticizer concentration. In all PLA/plasticizer systems investigated, when the blend T_g approaches room temperature, a stepwise change in the mechanical properties of the system is observed. The elongation at break drastically increases, whereas tensile strength and modulus decrease. This behavior occurs at a plasticizer concentration that depends on the T_g‐depressing efficiency of the plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1731–1738, 2003     

Starch esters with improved mechanical properties through melt compounding with nanoclays

Biobased nanocomposites were manufactured through the melt intercalation of nanoclays and starch esters synthesized at the Fraunhofer Institute for Applied Polymer Research (IAP) from high amylose starch. Starch acetates (SAs) and starch propionates (SPs) were tested in combination with glycerol triacetate (triacetin) as a plasticizer for concentrations up to 30 and 20 wt %, respectively, with different types of organomodified and unmodified montmorillonites (MMTs). The mechanical properties of injection‐molded test bars were determined by a tensile experiment giving the strength, modulus, and elongation of the composites. X‐ray diffraction (XRD) analysis and transmission electron microscopy (TEM) were used to study clay dispersion and intercalation/exfoliation. Dynamic mechanical analysis was used to track the temperature dependence of the storage modulus and tan δ behavior of the starch/clay hybrid. Because they were the best performing compositions, SP with 5 wt % plasticizer and SA with 20 wt % plasticizer were filled with 5 wt % nanoclay. For SP, a certain increase in modulus was observed for all clays. However, the strength was practically unchanged, and the elongation decreased in most cases. One exception was found for the 2.5 wt % organomodified clay composition, where the elongation increased. For SA, the addition of 5 wt % nanoclay always increased the strength and modulus, in one case up to 60 and 75%, respectively. In the particular case with 5 wt % unmodified clay, the strength, modulus, and elongation increased by 30, 40, and 1000%, respectively. This was a dramatic improvement in the ductility of the material without losses in the strength and stiffness. XRD and TEM revealed the existence of exfoliated modified clay throughout the starch matrix, whereas for the unmodified case (with the exceptional increase in the elongation), no intercalation was observed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The effect of citrate ester plasticizers on the thermal and mechanical properties of poly(DL‐lactide)

Citrate esters triethyl citrate, tributyl citrate, and acetyl tributyl citrate were used as plasticizers for amorphous poly(D,L ‐lactide) (PDLLA). The resultant compositions were analyzed by means of differential scanning calorimetry (DSC), dynamic mechanical thermal analysis, and tensile testing to investigate the properties of the blends. Glass transition temperatures (T_gs) obtained by DSC were also compared to theoretically calculated T_gs. Increasing plasticizer content decreased the resultant T_g of the blend with plasticizer efficiency enhanced as the molecular weight of the citrate ester increased. However, in blends with high plasticizer content, a lack of miscibility also occurred with increased molecular weight. Theoretical results were comparable with those obtained experimentally at compositions, which were miscible. Increasing plasticizer content increased the ductility and decreased the strength of the polymer. The addition of 10 wt % plasticizer to PDLLA decreased tensile strength by over 50% with the deterioration larger at higher concentrations of plasticizer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Poly(methyl methacrylate) toughened by ethylene‐vinyl acetate copolymer: Physico‐mechanical,thermal, and chemical properties

Blends of poly(methyl methacrylate) (PMMA) with different composition viz., 5, 10, 15, and 20 wt % of ethylene‐vinyl acetate (EVA) copolymer were prepared by extrusion in a corotating twin screw extruder. These prepared PMMA/EVA blends have been characterized for physicomechanical properties such as density, surface hardness, izod impact strength, tensile strength, tensile elongation, and tensile modulus. The chemical aging and heat aging tests were performed on the blends by exposing them to different chemical environments and to 80°C for 168 h respectively. The influence of chemical aging and heat ageing on the mechanical performance of PMMA/EVA blends has been studied. The PMMA/EVA blends were also characterized for thermal properties such as vicat softening point (VSP) and melt flow index (MFI). That means significant improvement in impact strength of PMMA was noticed after incorporation of EVA into PMMA matrix and it lies in the range 19.1–31.96 J/m. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effects of thermoplastic poly(ether-ester) elastomer and bentonite nanoclay on properties of poly(lactic acid)

This work presented the influence of thermoplastic poly(ether-ester) elastomer (TPEE) and bentonite (BTN) on improving the mechanical and thermal properties of poly(lactic acid) (PLA). PLA was initially melt mixed with TPEE at six different loadings (5–30 wt%) on a twin screw extruder and then injection molded. The mechanical tests revealed an increasing impact strength and elongation at break with increasing TPEE loading, but a diminishing Young's modulus and tensile strength with respect to pure PLA. The blend at 30 wt% TPEE provided the optimum improvement in toughness, exhibiting an increase in the impact strength and elongation at break by 3.21- and 10.62-fold over those of the pure PLA, respectively. Scanning electron microscopy analysis illustrated a ductile fractured surface of the blends with the small dispersed TPEE domains in PLA matrix, indicating their immiscibility. The 70/30 (wt/wt) PLA/TPEE blend was subsequently filled with three loadings of BTN (1, 3, and 5 parts by weight per hundred of blend resin [phr]), where the impact strength, Young's modulus, tensile strength and thermal stability of all the blends were improved, while the elongation at break was deteriorated. Among the three nanocomposites, that with 1 phr BTN formed exfoliated structure and so exhibited the highest impact strength, elongation at break, and tensile strength compared to the other intercalated nanocomposites. Moreover, the addition of BTN was found to increase the thermal stability of the neat PLA/TPEE blend due to the barrier properties and high thermal stability of BTN.     

Thermal and mechanical properties of poly(lactic acid)/starch/methylenediphenyl diisocyanate blending with triethyl citrate

Triethyl citrate (TC) was added as a plasticizer to a blend of poly(lactic acid) (PLA) and starch in the presence of methylenediphenyl diisocyanate (MDI). As expected, TC improved the elongation at break and toughness and, at the same time, decreased the tensile strength and modulus. However, TC did not significantly affect the coupling effects of MDI on starch and PLA. The tensile strength of the blend with MDI was much greater than the tensile strength without MDI at the same TC level. The tensile properties of the blend changed dramatically as the TC concentration increased from 5 to 12.5%. At a TC concentration of 7.5%, the blend produced desirable elongation and toughness with fairly good tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2947–2955, 2003     

过氧化物交联聚烯烃弹性体的性能

采用过氧化物交联，讨论了交联剂、共交联剂、补强填充剂以及增地采用茂金属催化剂合成的乙烯－辛烯共聚物（ＰＯＥ）的物理机械性能的影响。和过氧化物交联后，ＰＯＥ的拉伸强度、扯断伸长率和扯断永久变形大幅度下降。加入共交联剂，可以提高交联程度，缩短硫化时间。加入炭黑，可以起到补强作用。提高１００％定伸应力、撕裂强度、伸强度和硬度，减小扯断伸长率和扯断永久变形。加入增塑剂降低了某些力学性能，但扯断伸长率增加，     

Influence of processing condition and carbon nanotube on mechanical properties of injection molded multi‐walled carbon nanotube/poly(methyl methacrylate) nanocomposites

In this work, multi‐walled carbon nanotubes (MWCNT) and poly(methyl methacrylate) (PMMA) pellets were compounded via corotating twin‐screw extruder. The produced MWCNT/PMMA nanocomposite pellets were injection molded. The effect of MWCNT concentration, injection melt temperature and holding pressure on mechanical properties of the nanocomposites were investigated. To examine the mechanical properties of the MWCNT/PMMA nanocomposites, tensile test, charpy impact test, and Rockwell hardness are considered as the outputs. Design of experiments (DoE) is done by full factorial method. The morphology of the nanocomposites was performed using scanning electron microscopy (SEM). The results revealed when MWCNT concentration are increased from 0 to 1.5 wt %, tensile strength and elongation at break were reduced about 30 and 40%, respectively, but a slight increase in hardness was observed. In addition, highest impact strength belongs to the nanocomposite with 1 wt % MWCNT. This study also shows that processing condition significantly influence on mechanical behavior of the injection molded nanocomposite. In maximum holding pressure (100 bar), the nanocomposites show highest tensile strength, elongation, impact strength and hardness. According to findings, melt temperature has a trifle effect on elongation, but it has a remarkable influence on tensile strength. In the case of impact strength, higher melt temperature is favorable. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43738.     

The effect of an epoxidized plasticizer on the thermo-oxidative ageing of poly(vinyl chloride)/epoxidized natural rubber thermoplastic elastomers

The effects of an epoxidized plasticizer on the mechanical properties and thermo-oxidative ageing behaviour of poly(vinyl chloride)/epoxidized natural rubber thermoplastic elastomers (TPEs) were investigated. Aged and unaged blends were characterized by FTIR, tensile properties, tear strength, hardness and dynamic mechanical analysis (DMA). The properties of the epoxidized soya oil (ESO) plasticized TPEs were compared with those of the di-2-ethylhexylphthalate (DOP) plasticized counterparts. The presence of epoxide groups in ESO has been shown to produce two conflicting effects. On the one hand, the presence of excessive epoxide groups has resulted in poor ageing behaviour. On the other hand, it has resulted in a good interaction and compatibility with PVC/ENR. It was found that the tensile strength of the ESO plasticized blends were comparable with the DOP plasticized ones, but the elongation at break (EB) of the ESO blends fell short of that of the DOP blends. Also the retention of both tensile properties for the ESO blends was poorer than for DOP blends. Hardening and embrittlement also occurred in the ESO blends. Despite these weaknesses, ESO could be an ideal plasticizer for the PVC/ENR system as indicated by plasticizer permanence and the greater efficiency of plasticization. © 1998 SCI.     

碳纤维改性HA/PMMA生物复合材料力学性能的研究

采用原位合成与溶液共混相结合的方法,制备了短切碳纤维增强纳米羟基磷灰石(HA)/聚甲基丙烯酸甲酯(PMMA)生物复合材料。研究了碳纤维的含量和长度对HA/PMMA复合材料结构和力学性能的影响。采用万能材料试验机和扫描电子显微镜对复合材料的力学性能及断面的微观形貌进行了测试和表征。结果表明:碳纤维在HA/PMMA复合材料中分布均匀,有效提高了复合材料的力学性能;碳纤维含量为4%时,复合材料的拉伸强度、弯曲强度、压缩强度和弹性模量等均达到最大值;复合材料的断裂伸长率随碳纤维含量的增加而减小;当碳纤维含量一定时,随其长度的增加,复合材料的拉伸强度、弯曲强度和弹性模量均增加,但断裂伸长率降低。     

PPC/PBAT共混复合材料性能的研究

采用双螺杆挤出机制备了聚碳酸亚丙酯/聚对苯二甲酸-己二酸丁二酯共混复合材料(PPC/PBAT)。考察了PPC、扩链剂和增塑剂用量对该共混材料力学性能和流变性能的影响。研究结果表明:在PPC/PBAT共混体系中,随PPC用量的增加,拉伸强度逐渐提高,而断裂伸长率和熔体流动速率(MFR)不断降低;而扩链剂二苯基甲烷二异氰酸酯(MDI)的引入,改善了PPC与PBAT的相容性,且随着MDI用量的增加,共混材料的拉伸强度和断裂伸长率呈增加趋势,而MFR则持续降低;另外,当体系中加入增塑剂柠檬酸三丁酯后,随其用量的增加,PPC/PBAT共混材料的拉伸强度降低,而断裂伸长率和MFR持续提高。     

Mechanical and thermal properties of starch‐filled poly(D,L‐lactic acid)/poly(hydroxy ester ether) biodegradable blends

The mechanical, structural, and thermal properties of injection‐molded composites of granular cornstarch, poly(D ,L ‐lactic acid) (PDLLA), and poly(hydroxy ester ether) (PHEE) were investigated. These composites had high tensile strengths, ranging from 17 to 66 MPa, at starch loadings of 0–70 wt %. Scanning electron microscopy micrographs of fracture specimens revealed good adhesion between the starch granule and the polymer matrix, as evidenced by broken starch granules. The adhesion of the starch granules to the polymer matrix was the greatest when the matrix PDLLA/PHEE ratios ranged from zero to unity. At a PDLLA/PHEE ratio of less than unity, as the starch content increased in the composites, there was an increase in the tensile strength and modulus, with a concurrent decrease in elongation. The effects of starch on the mechanical properties of starch/PDLLA composites showed that as the starch content of the composite increased, the tensile strength and elongation to break decreased, whereas Young's modulus increased. In contrast, the tensile strength of starch/PHEE composites increased with increasing starch content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1775–1786, 2003     

The effect of the addition of poly(styrene‐co‐glycidyl methacrylate) copolymer on the properties of polylactide/poly(methyl methacrylate) blend

The effect of the addition of poly(styrene‐co‐glycidyl methacrylate) P(S‐co‐GMA) copolymer on the properties of melt blended polylactide/poly(methyl methacrylate) (PLA/PMMA) 80/20 (wt %) composition was studied. In the literature high ductility levels were achieved by melt blending PLA with different additives. However, the gained ductility was counter balanced with drastic drops in strength and modulus values. The novelty of this work was the preparation of PLA‐based blends with polylactide content higher than 75 wt % which showed an impact resistance value improvement of about 60% compared with the neat PLA and maintained similar tensile strength and modulus values as well as glass transition temperature to neat PLA. The addition of only 3 pph of copolymer to PLA/PMMA blend improved the impact resistance almost 100%. The chemical reaction between PLA/PMMA blend and P(S‐co‐GMA) copolymer were analyzed by FTIR, rotational rheometry, and GPC/SEC. Phase structure and morphology were studied by Differential Scanning Calorimetry and Scanning Electronic Microscopy. Tensile and impact properties as well as thermal stability were also studied. Results showed that as the amount of copolymer in the blend was increased then higher was average molecular weight and polydispersity index. After the addition of P(S‐co‐GMA) copolymer to the PLA/PMMA blend the impact resistance, elongation at break and thermal stability were improved while tensile strength and elastic modulus remained almost unaltered. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43935.     

Physical Properties of Plasticized Poly(vinyl chloride) Blended with Poly(methyl methacrylate) Nanoparticles Synthesized by Differential Microemulsion Polymerization

In this work, poly(methyl methacrylate) (PMMA) nanoparticles synthesized by differential micro emulsion polymerization were used to improve the physical properties of plasticized poly(vinyl chloride) (PVC). PVC, plasticizer (40 phr), heat stabilizer (2 phr), and lubricant (0.2 phr) were melt-mixed with varied amount of the PMMA nanoparticles (3, 5, 7, and 9 phr) on a two-roll mill, followed by compression molding. The results showed that the tensile strength, Young's modulus, tear strength, and thermal stability were improved, but the elongation at break deteriorated with increased PMMA content. Moreover, the flammability of the plasticized PVC was not improved by the PMMA nanoparticles.     

Poly(lactic acid) properties as a consequence of poly(butylene adipate‐co‐terephthalate) blending and acetyl tributyl citrate plasticization

This study was aimed at the modulation of poly(lactic acid) (PLA) properties by the addition of both a low‐molecular‐weight plasticizer, acetyl tributyl citrate (ATBC), and a biodegradable aliphatic–aromatic copolyester, poly(butylene adipate‐co‐terephthalate) (PBAT). PLA/PBAT, PLA/ATBC, and PLA/PBAT/ATBC mixtures with 10–35 wt % ATBC and/or PBAT were prepared in a discontinuous laboratory mixer, compression‐molded, and characterized by thermal, morphological, and mechanical tests to evaluate the effect of the concentration of either the plasticizer or copolyester on the final material flexibility. Materials with modulable properties, Young's modulus in the range 100–3000 MPa and elongation at break in the range 10–300%, were obtained. Moreover, thermal analysis showed a preferential solubilization of ATBC in the PBAT phase. Gas permeability tests were also performed to assess possible use in food packaging applications. The results are discussed with particular emphasis toward the effects of plasticization on physical blending in the determination of the phase morphology and final properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Facile way to disperse single‐walled carbon nanotubes using a noncovalent method and their reinforcing effect in poly(methyl methacrylate) composites

In this work, a noncovalent method was used to functionalize and thereby disperse single‐walled carbon nanotubes (SWCNTs) in dimethylformamide with poly[methyl methacrylate‐co‐(fluorescein O‐acrylate)] as a surfactant, and then the resultant poly(methyl methacrylate) (PMMA)‐based nanocomposites were fabricated via solution casting. The dispersion level of carbon nanotubes in the solvent was investigated by means of scanning electron microscopy and atomic force microscopy. The results showed that carbon nanotubes were well wrapped by the surfactant, and small carbon nanotube bundles several nanometers or less in diameter and several micrometers in length were obtained. Both scanning electron microscopy and transmission electron microscopy confirmed the uniform dispersion of SWCNTs in the PMMA matrix. The mechanical properties of the composites were determined with a universal tension tester. The PMMA composite containing 2 wt % SWCNTs showed improved tensile properties versus neat PMMA, showing 56 and 30% enhancements of the tensile modulus and tensile stress, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚烯烃弹性体的物理机械性能

讨论了聚烯烃热塑性弹性体乙烯－辛烯共聚物的结晶行为,填充增强剂、增塑剂和辛烯含量等因素对ＰＯＥｓ物理机械性能的影响。结果表明,ＰＯＥｓ具有良好的物理机械性能,加入炭黑有较好的增强作用,拉伸强度,撕裂强度、１００％定伸应力邵尔Ａ型硬度提高,冲击弹性和扯断伸长率下降;加入碳酸下和石蜡油,ＰＯＥｓ综合性能有所下降,加入石蜡油可降低试样的邵尔Ａ型硬度。无论是添加增强剂或增塑剂,ＰＯＥｓ综合性能有所下降。加     

Thermal and mechanical properties of poly(ε‐caprolactone) crosslinked with γ radiation in the presence of triallyl isocyanurate

Poly(?‐caprolactone) was crosslinked by γ radiation in the presence of triallyl isocyanurate. The influence of γ‐radiation crosslinking on the thermal and mechanical properties of poly(?‐caprolactone)/triallyl isocyanurate was investigated. Differential scanning calorimetry analyses showed differences between the first and second scans. Dynamic mechanical analysis showed an increase in the glass‐transition temperature as a result of the radiation crosslinking of poly(?‐caprolactone). Thermogravimetric analysis showed that γ‐radiation crosslinking slightly improved the thermal stability of poly(?‐caprolactone). The γ radiation also strongly influenced the mechanical properties. At room temperature, crosslinking by radiation did not have a significant influence on the Young's modulus and yield stress of poly(?‐caprolactone). However, the tensile strength at break and the elongation at break generally decreased with an increase in the crosslinking level. When the temperature was increased above the melting point, the tensile strength at break, elongation at break, and Young's modulus of poly(?‐caprolactone) were also reduced with an increase in the crosslinking level. The yield stress disappeared as a result of the disappearance of the crystallites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2676–2681, 2007