Probing interfacial mobility profiles via the impact of nanoscopic confinement on the strength of the dynamic glass transition

Soft Matter ◽  
2011 ◽  
Vol 7 (11) ◽  
pp. 5260 ◽  
Author(s):  
Cinzia Rotella ◽  
Michael Wübbenhorst ◽  
Simone Napolitano
Keyword(s):  
Glass Transition ◽  
The Impact ◽  
Interfacial Mobility

scholarly journals Investigation of the functional network modifier loading on the stoichiometric ratio of epoxy resins and their dielectric properties

2021 ◽  
Author(s):  
Istebreq A. Saeedi ◽  
Sunny Chaudhary ◽  
Thomas Andritsch ◽  
Alun S. Vaughan
Keyword(s):  
Glass Transition ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Epoxy Resins ◽  
Functional Network ◽  
Cross Linking ◽  
Network Modifier ◽  
Epoxy Resin System ◽  
The Cross ◽  
The Impact

AbstractReactive molecular additives have often been employed to tailor the mechanical properties of epoxy resins. In addition, several studies have reported improved electrical properties in such systems, where the network architecture and included function groups have been modified through the use of so-called functional network modifier (FNM) molecules. The study reported here set out to investigate the effect of a glycidyl polyhedral oligomeric silsesquioxane (GPOSS) FNM on the cross-linking reactions, glass transition, breakdown strength and dielectric properties of an amine-cured epoxy resin system. Since many previous studies have considered POSS to act as an inorganic filler, a key aim was to consider the impact of GPOSS addition on the stoichiometry of curing. Fourier transform infrared spectroscopy revealed significant changes in the cross-linking reactions that occur if appropriate stoichiometric compensation is not made for the additional epoxide groups present on the GPOSS. These changes, in concert with the direct effect of the GPOSS itself, influence the glass transition temperature, dielectric breakdown behaviour and dielectric response of the system. Specifically, the work shows that the inclusion of GPOSS can result in beneficial changes in electrical properties, but that these gains are easily lost if consequential changes in the matrix polymer are not appropriately counteracted. Nevertheless, if the system is appropriately optimized, materials with pronounced improvements in technologically important characteristics can be designed.

Silane Functionalized Ethylene/Diene Copolymer Modifiers in Composites of Heterophasic Polypropylene and Microsilica

2007 ◽  
Vol 15 (5) ◽  
pp. 343-355 ◽  
Author(s):  
S. Lipponen ◽  
P. Pietikäinen ◽  
U. Vainio ◽  
R. Serimaa ◽  
J.V. Seppälä
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Impact Strength ◽  
Ambient Temperature ◽  
Metallocene Catalyst ◽  
The Poor ◽  
Rubber Toughened ◽  
Rubbery Phase ◽  
The Impact

Ethylene/1,7-octadiene copolymer was polymerised with metallocene catalyst and hydrosilylated to form silane functionalised polyethylenes (PE-co-SiX, X=Cl, OEt, Ph). The functionalised species were tested as modifiers in composites of rubber toughened polypropylene (heterophasic PP, hPP) and microsilica filler (μSi). A metallocene-based functionalised PE (PE-co-SiF) produced earlier in our laboratory and three commercial grades of functionalised polyolefins (one PE- and two PP-based) were used as reference modifiers. Major differences were seen in the toughness of the composites both above and below the glass transition temperature (Tg) of PP. In addition to increasing the stiffness, the microsilica filler enhanced the toughness of the heterophasic polypropylene by over 200% at ambient temperature. Below the Tg of PP (at −20 °C), the influence of μSi was the opposite and the impact strength of the hPP/μSi composite was below that of unfilled hPP. With the addition of just 2 wt% of functionalised polyethylene, the poor cold toughness of hPP/μSi composite was improved by nearly 100%. With the same addition, the toughness of the composites at ambient temperature was improved by 50 to 100% compared with the unfilled hPP. This behaviour was explained by significant changes in the fracture mechanism. Addition of functionalised PE increased the concentration of microsilica in the rubbery phase, allowing the crack to enter that phase. The rubbery phase was also able to absorb a large amount of impact energy below the glass transition temperature of PP.

scholarly journals INFLUENCE OF ENVIRONMENTAL FACTORS ON PHYSICAL-MECHANICAL PROPERTIES OF POLYDIMETHYL ETHER OF NORBORENE -2;3-DICARBOXYLIC ACID

2017 ◽  
Vol 60 (5) ◽  
pp. 68 ◽  
Author(s):  
Galina S. Bozhenkova ◽  
Alexandra N. Tarakanovskaya ◽  
Oksana D. Tarnovskaya ◽  
Roman V. Ashirov
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Hydrochloric Acid ◽  
Environmental Factors ◽  
Dicarboxylic Acid ◽  
Uv Radiation ◽  
Accelerated Aging ◽  
The Impact

The article is devoted to the production of polymer by metathesis ring-opening polymerization under the influence of ruthenium initiator of type of Hoveyda-Grubbs II generation. The monomer used the mixture of dimethyl ether norbornene-2;3-dicarboxylic acid. The monomer was prepared by the Diels-Alder reaction of dicyclopentadiene and dimethyl maleate. The polymer was prepared in bulk of the monomer mixture. In this paper we have studied the physical and mechanical properties polydimethyl ether of norbornene-2;3-dicarboxylic acid; and assessed the impact of environmental factors on the change in properties of the polymer. As environmental factors; light; UV radiation; water; 0.1 M hydrochloric acid were applied; and accelerated aging conditions; which were held in a climate chamber. During performance we found that maintaining the polymer samples in the UV light chamber led to the slight increase in flexural modulus. In contrast; the polymer storage in water and in a hydrochloric acid solution for two months resulted in a slight decrease in the modulus of elasticity in bending index. These factors did not affect the change in the glass transition temperature of the polymer. Under the conditions of accelerated aging conducted for 1; 2 and 6 days after two cycles we observed the drop in modulus for bending of 8.5%; after 6 cycles of 13%. The glass transition temperature of polydimethyl ether of norbornene-2;3-dicarboxylic acid after 6 cycles decreased by only 3.4% in the climatic chamber. Studies have shown that the resulting polymer is resistant to water; hydrochloric acid; light and UV radiation; as well as it saves properties at a sufficient level for operation at conditions of accelerated aging. It should be noted that the tested polymer was prepared without additives; stabilizers and antioxidants. The proposed polymer can be used as a structural material for machine parts; including bulky.For citation:Bozhenkova G.S.; Tarakanovskaya A.N.; Tarnovskaya O.D.; Ashirov R.V. Influence of environmental factors on physical-mechanical properties of polydimethyl ether of norborene -2;3-dicarboxylic acid. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 68-73

scholarly journals Investigation on compatibility of PLA/PBAT blends modified by epoxy-terminated branched polymers through chemical micro-crosslinking

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Bo Wang ◽  
Yujuan Jin ◽  
Kai’er Kang ◽  
Nan Yang ◽  
Yunxuan Weng ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Sem Analysis ◽  
Branched Polymers ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Butylene Terephthalate ◽  
The Difference ◽  
Physical And Chemical ◽  
The Impact

AbstractIn this study, a type of epoxy-terminated branched polymer (ETBP) was used as an interface compati- bilizer to modify the poly lactic acid (PLA)/poly(butylene adipate-co-butylene terephthalate) (PBAT) (70/30) blends. Upon addition of ETBP, the difference in glass transition temperature between PLA and PBAT became smaller. By adding 3.0 phr of ETBP, the elongation at break of the PLA/PBAT blends was found increased from 45.8% to 272.0%; the impact strength increased from 26.2 kJ·m−2 to 45.3 kJ·m−2. In SEM analysis, it was observed that the size of the dispersed PBAT particle decreased with the increasing of ETBP content. These results indicated that the compatibility between PLA and PBAT can be effectively enhanced by using ETBP as the modifier. The modification mechanism was discussed in detail. It proposes that both physical and chemical micro-crosslinking were formed, the latter of which was confirmed by gel content analysis.

Studies on Mechanical and Thermal Properties of Epoxy Resin Modified by Fluorine-Containing Silicone

2013 ◽  
Vol 401-403 ◽  
pp. 713-716
Author(s):  
Cheng Fang ◽  
Dong Bo Guan ◽  
Wei Guo Yao ◽  
Shou Jun Wang ◽  
Hui An
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Bending Strength ◽  
Mechanical And Thermal Properties ◽  
Curing Agent ◽  
Epoxy System ◽  
Resin Curing ◽  
The Impact ◽  
Modified Epoxy

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.

scholarly journals Review of Recent Developments of Glass Transition in PVC Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4336
Author(s):  
Jolanta Tomaszewska ◽  
Tomasz Sterzyński ◽  
Aneta Woźniak-Braszak ◽  
Michał Banaszak
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermomechanical Analysis ◽  
Mechanical Analysis ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
Recent Developments ◽  
Dielectric Thermal Analysis ◽  
The Impact

This review addresses the impact of different nanoadditives on the glass transition temperature (Tg) of polyvinyl chloride (PVC), which is a widely used industrial polymer. The relatively high Tg limits its temperature-dependent applications. The objective of the review is to present the state-of-the-art knowledge on the influence of nanofillers of various origins and dimensions on the Tg of the PVC. The Tg variations induced by added nanofillers can be probed mostly by such experimental techniques as thermomechanical analysis (TMA), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and dielectric thermal analysis (DETA). The increase in Tg is commonly associated with the use of mineral and carbonaceous nanofillers. In this case, a rise in the concentration of nanoadditives leads to an increase in the Tg due to a restraint of the PVC macromolecular chain’s mobility. The lowering of Tg may be attributed to the well-known plasticizing effect, which is a consequence of the incorporation of oligomeric silsesquioxanes to the polymeric matrix. It has been well established that the variation in the Tg value depends also on the chemical modification of nanofillers and their incorporation into the PVC matrix. This review may be an inspiration for further investigation of nanofillers’ effect on the PVC glass transition temperature.

scholarly journals Shape-Memory Properties of 3D Printed Cubes from Diverse PLA Materials with Different Post-Treatments

Technologies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 71
Author(s):  
Guido Ehrmann ◽  
Bennet Brockhagen ◽  
Andrea Ehrmann
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Shape Memory ◽  
Poly Lactic Acid ◽  
Safety Equipment ◽  
Shape Memory Properties ◽  
3D Printed ◽  
Proper Material ◽  
The Impact

Poly(lactic acid) (PLA) belongs to the 3D printable materials which show shape-memory properties, i.e., which can recover their original shape after a deformation if they are heated above the glass transition temperature. This makes PLA quite an interesting material for diverse applications, such as bumpers, safety equipment for sports, etc. After investigating the influence of the infill design and degree, as well as the pressure orientation on the recovery properties of 3D printed PLA cubes in previous studies, here we report on differences between different PLA materials as well as on the impact of post-treatments after 3D printing by solvents or by heat. Our results show not only large differences between materials from different producers, but also a material-dependent impact of the post treatments. Generally, it is possible to tailor the mechanical and recovery properties of 3D printed PLA parts by choosing the proper material in combination with a chemical or temperature post-treatment.

Interplay between Core and Interfacial Mobility and Its Impact on the Measured Glass Transition: Dielectric and Calorimetric Studies

2016 ◽  
Vol 120 (13) ◽  
pp. 7373-7380 ◽  
Author(s):  
Magdalena Tarnacka ◽  
Ewa Kaminska ◽  
Kamil Kaminski ◽  
C. Michael Roland ◽  
Marian Paluch
Keyword(s):  
Glass Transition ◽  
Calorimetric Studies ◽  
Interfacial Mobility

CONNECTION BETWEEN STRUCTURAL CHANGES OF IRRIADIATED POLYETHER ETHER KETONE AND MECHANICAL PROPERTIES

Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 95-101
Author(s):  
Aneta NIEMIEC
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Structural Changes ◽  
Radiation Energy ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
The Impact ◽  
The Degree Of Crystallinity

The article presents the results of research on the impact of structural changes in polyether ether ketone (PEEK) on its mechanical properties. The polymer was exposed to gamma radiation at a dose of 50 and 150 kGy, and the radiation energy was 4 MeV. Changes in the degree of crystallinity and the related changes in the glass transition and melting temperature for the polymer were determined by differential scanning calorimetry (DSC). Mechanical properties were determined using the micro-mentoring method. The tests showed a change in the degree of crystallinity in the range of several degrees and a significant increase in the glass transition temperature. In terms of mechanical properties, the reduction of hardness and Young’s modulus was observed. Observed changes, especially in terms of changes in the structure of the polymer under the influence of radiation, are difficult to explain, which requires conducting further research, especially in the range of irradiation parameters used. Further research is important because PEEK is used in many fields, especially in conditions conducive to corrosion and the influence of radiation.

scholarly journals Preparation and Characterization of Glass-Fiber-Reinforced Modified Polyphenylene Oxide by a Direct Fiber Feeding Extrusion Process

2021 ◽  
Vol 11 (21) ◽  
pp. 10266
Author(s):  
SeungJae Ahn ◽  
Jae-Chul Lee ◽  
Ki-Young Kim
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Impact Strength ◽  
Fiber Length ◽  
Extrusion Process ◽  
Fiber Reinforced ◽  
Feeding Method ◽  
Polyphenylene Oxide ◽  
Glass Fiber Reinforced ◽  
The Impact

Polyphenylene oxide (PPO) polymers have good mechanical, electrical, and thermal properties, but they have poor processability owing to their quite high melt viscosity. This hinders the manufacturing processes of fiber-reinforced thermoplastics that have enhanced mechanical and physical properties. Although PPO was modified by blending with polystyrene (PS) or polyamide to improve processability, the modified PPO (mPPO) still had a high melt viscosity compared with other polymers. Thus, the fiber-reinforced mPPO is manufactured by compounding with chopped fiber, while various methods are applied to manufacture the fiber-reinforced polypropylene and polyamide in order to improve properties. One of the methods is a direct fiber feeding method, which can keep the longer fiber length because of a direct and continuous roving yarn feeding without chopping. Therefore, the composite manufactured by the direct fiber feeding method is expected to improve the mechanical properties. Hence, this study aims to investigate the feasibility of a direct fiber feeding extrusion process for manufacturing glass-fiber-reinforced mPPO or GFmPPO. The manufactured GF/mPPO composites exhibited increased tensile and flexural properties as the fiber content increased up to 50 wt% of GF owing to the predominant effects of fiber content.. Nevertheless, the larger core area in the cross-section micrograph of the tensile specimen of the GF/mPPO composite with 50 wt% of GF was observed to reduce the fiber efficiency factor for tensile strength. Meanwhile, the impact strength of the GF/mPPO composites decreased with increasing GF content. This is attributed to the insufficient fiber length for the impact strength. As the GF content increased, the glass transition temperature slightly decreased. This result was interpreted as being a result of thermal degradation during the extrusion process to manufacture the GF/mPPO masterbatch. The results of the dynamic mechanical analyses, e.g., storage modulus and tan δ, show the good correlation with the increased flexural modulus, the decreased glass transition temperature, and the impact strength as the GF content increased.

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