New Class of Reactive Polymer Modifiers for Asphalt: Mitigation of Moisture Damage

2000 ◽  
Vol 1728 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Glen Crossley ◽  
Simon Hesp
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
Asphalt Concrete ◽  
Lower Cost ◽  
Water Immersion ◽  
Polymerization Process ◽  
Reactive Polymer ◽  
New Class ◽  
Added Benefit ◽  
Polymer Modifiers

A new class of reactive polymer modifiers designed to improve binder-aggregate adhesion in asphalt concrete was evaluated. Using a controlled free radical polymerization process, polyisoprene was prepared with short blocks of reactive amino- or silane-functional monomer at one end of the polymer chain. The reactive polymers so synthesized were tested with a modified version of the Tunnicliff-Root method (ASTM D4867) for measuring retained tensile strengths after water immersion moisture conditioning at 60°C for 24 h. It was found that the retained tensile strength of the unmodified samples was 53 percent, and the retained tensile strength of the regular polyisoprene-modified control samples was between 57 and 69 percent, depending on the polymer molecular weight and content. The best retained tensile strengths of 86 and 90 percent, respectively, were obtained with samples modified with 3 and 5 percent by weight of the higher-molecular-weight silane-functional polyisoprene. The method for obtaining the desired effect is flexible; lower-cost monomers, such as butadiene, and more common polymerization methods, such as emulsion or anionic polymerization techniques, may be used equally well to produce polymers with similar or better performance characteristics. An added benefit is that the tested polymers imparted significant improvements in low-temperature performance measured with the thermal stress restrained cooling test.

New Class of Reactive Polymer Modifiers for Asphalt: Mitigation of Low-Temperature Damage

2000 ◽  
Vol 1728 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Glen A. Crossley ◽  
Simon A. M. Hesp
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Polymerization Process ◽  
Stable Mode ◽  
Reactive Polymer ◽  
New Class ◽  
Specimen Test ◽  
Temperature Damage ◽  
Styrene Butadiene ◽  
Polymer Modifiers

Results from the low-temperature performance evaluation of a new class of reactive polymer modifiers designed to improve binder-aggregate adhesion in asphalt concrete are discussed. A living free radical polymerization process was used to prepare polyisoprene (PI) with short blocks of reactive silane-functional monomer at one end of the polymer chain. Performance was evaluated with the thermal stress restrained specimen test at a cooling rate of-10°C/h. The results obtained were compared with those for unmodified and styrene-butadiene (SB)-modified mixes. When added at 3 and 6 percent by weight of the binder, SB reduced the fracture temperature of the asphalt concrete by 6°C and 9°C, respectively. Similar results were obtained with the reactive polymers. However, although all the SB-modified samples failed in a catastrophic mode, none of the samples containing the silane-functional PI did. It is hypothesized that these polymers toughened the asphalt to an extent that cracks were only able to grow in a stable mode as opposed to an unstable mode or that localized yielding occurred. The method for obtaining the desired toughening effect is flexible; lower-cost monomers, such as butadiene, and more common polymerization methods, such as emulsion or anionic polymerization techniques, could be used equally well to produce polymers with similar or better performance characteristics. An added benefit is that the tested polymers were able to improve the stripping resistance of the mix significantly.

scholarly journals KETAHANAN CAMPURAN AC-WC MENGGUNAKAN LATEKS TERHADAP AIR

2020 ◽  
Vol 20 (2) ◽  
pp. 125-136
Author(s):  
Sri Sunarjono ◽  
Nurul Hidayati ◽  
Adi Indra Pratama
Keyword(s):  
Tensile Strength ◽  
Residual Strength ◽  
Asphalt Concrete ◽  
Water Immersion ◽  
Asphalt Mixture ◽  
Indirect Tensile Strength ◽  
Strength Index ◽  
Influence Of Water ◽  
Scale Test ◽  
Indirect Tensile

Abstract This paper presents the results of research on the durability of Asphalt Concrete-Wear Asphalt (AC-WC) mixture using latex material to water immersion. Resistance to warm water immersion is intended to measure the durability of asphalt mixture in serving traffic loads against the influence of water and temperature factors. The use of latex material is intended to improve the performance of the mixture. This research uses a laboratory-scale test. The specimen of AC-WC added with latex was tested for its tensile strength using the Indirect Tensile Strength (ITS) test. Other specimens are immersed in water at 60°C with a continuous and periodic soaking system. The continuous immersion was carried out for 0, 24, 48, and 72 hours, while the periodic immersion was carried out for 12 hours soaked and 12 hours exposed alternately. The durability was analyzed using the Residual Strength Index indicator. The analysis shows that the addition of latex increased the tensile strength of the AC-WC mixture based on the ITS test results. The AC-WC mixture added with latex can increase its resistance to continuous and periodic immersion, by increasing the residual strength index and decreasing IKS with increasing immersion time. Continuous immersion has a greater impact on reducing IKS than periodic. In specimens without latex, the decrease in IKS values between continuous and periodic soaking has the same pattern, but in specimens with latex, the pattern is different. Keywords: asphalt concrete; latex; water immersion; Indirect Tensile Strength; Residual Strength Index.  Abstrak Makalah ini menyajikan hasil penelitian mengenai ketahanan campuran beraspal Asphalt Concrete-Wearing Course (AC-WC) yang menggunakan bahan lateks terhadap rendaman air. Ketahanan terhadap perendaman air hangat dimaksudkan untuk mengukur daya tahan campuran aspal dalam melayani beban lalu lintas terhadap pengaruh faktor air dan temperatur. Penggunaan bahan lateks dimaksudkan untuk memperbaiki kinerja cam-puran. Penelitian ini menggunakan uji skala laboratorium. Kekuatan tarik benda uji AC-WC dengan lateks diuji menggunakan uji Indirect Tensile Strength (ITS). Benda uji yang lain direndam dalam air bertemperatur 60oC dengan sistem rendaman menerus dan rendaman berkala. Metode perendaman secara menerus dilakukan selama 0, 24 jam, 48 jam, dan 72 jam, sedangkan rendaman secara berkala dilakukan 12 jam direndam dan 12 jam diekspose secara bergantian. Tingkat keawetan dianalisis menggunakan indikator Indeks Kekuatan Sisa (IKS). Hasil analisis menunjukkan bahwa penambahan lateks meningkatkan kekuatan tarik campuran AC-WC berdasarkan hasil uji ITS. Ketahanan terhadap perendaman menerus dan berkala, campuran AC-WC menggu-nakan lateks meningkat, dengan meningkatnya indeks kekuatan sisa dan menurunnya IKS dengan bertambah-nya lama rendaman. Perendaman secara menerus memberi dampak yang lebih besar dalam menurunkan IKS dibanding perendaman berkala. Pada benda uji tanpa lateks, penurunan nilai IKS antara rendaman menerus dan rendaman berkala memiliki pola yang sama, namun pada benda uji dengan lateks pola penurunan nilai IKS berbeda. Kata-kata kunci: campuran beraspal; lateks; rendaman air; Indirect Tensile Strength; Indeks Kekuatan Sisa.

Conjugates of Classical DNA/RNA Binder with Nucleobase: Chemical, Biochemical and Biomedical Applications

2019 ◽  
Vol 26 (30) ◽  
pp. 5609-5624
Author(s):  
Dijana Saftić ◽  
Željka Ban ◽  
Josipa Matić ◽  
Lidija-Marija Tumirv ◽  
Ivo Piantanida
Keyword(s):  
Molecular Weight ◽  
Small Molecules ◽  
Biomedical Applications ◽  
Protein Targets ◽  
New Class ◽  
Rna Targets ◽  
Covalently Linked ◽  
Structural Aspects

: Among the most intensively studied classes of small molecules (molecular weight < 650) in biomedical research are small molecules that non-covalently bind to DNA/RNA, and another intensively studied class is nucleobase derivatives. Both classes have been intensively elaborated in many books and reviews. However, conjugates consisting of DNA/RNA binder covalently linked to nucleobase are much less studied and have not been reviewed in the last two decades. Therefore, this review summarized reports on the design of classical DNA/RNA binder – nucleobase conjugates, as well as data about their interactions with various DNA or RNA targets, and even in some cases protein targets are involved. According to these data, the most important structural aspects of selective or even specific recognition between small molecule and target are proposed, and where possible related biochemical and biomedical aspects were discussed. The general conclusion is that this, rather new class of molecules showed an amazing set of recognition tools for numerous DNA or RNA targets in the last two decades, as well as few intriguing in vitro and in vivo selectivities. Several lead research lines show promising advancements toward either novel, highly selective markers or bioactive, potentially druggable molecules.

scholarly journals Melt- vs. Non-Melt Blending of Complexly Processable Ultra-High Molecular Weight Polyethylene/Cellulose Nanofiber Bionanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 404
Author(s):  
Nur Sharmila Sharip ◽  
Hidayah Ariffin ◽  
Tengku Arisyah Tengku Yasim-Anuar ◽  
Yoshito Andou ◽  
Yuki Shirosaki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Yield Strength ◽  
Young’S Modulus ◽  
High Molecular Weight ◽  
Melt Processing ◽  
Cellulose Nanofiber ◽  
Melt Blending ◽  
Ultra High Molecular Weight

The major hurdle in melt-processing of ultra-high molecular weight polyethylene (UHMWPE) nanocomposite lies on the high melt viscosity of the UHMWPE, which may contribute to poor dispersion and distribution of the nanofiller. In this study, UHMWPE/cellulose nanofiber (UHMWPE/CNF) bionanocomposites were prepared by two different blending methods: (i) melt blending at 150 °C in a triple screw kneading extruder, and (ii) non-melt blending by ethanol mixing at room temperature. Results showed that melt-processing of UHMWPE without CNF (MB-UHMWPE/0) exhibited an increment in yield strength and Young’s modulus by 15% and 25%, respectively, compared to the Neat-UHMWPE. Tensile strength was however reduced by almost half. Ethanol mixed sample without CNF (EM-UHMWPE/0) on the other hand showed slight decrement in all mechanical properties tested. At 0.5% CNF inclusion, the mechanical properties of melt-blended bionanocomposites (MB-UHMWPE/0.5) were improved as compared to Neat-UHMWPE. It was also found that the yield strength, elongation at break, Young’s modulus, toughness and crystallinity of MB-UHMWPE/0.5 were higher by 28%, 61%, 47%, 45% and 11%, respectively, as compared to the ethanol mixing sample (EM-UHMWPE/0.5). Despite the reduction in tensile strength of MB-UHMWPE/0.5, the value i.e., 28.4 ± 1.0 MPa surpassed the minimum requirement of standard specification for fabricated UHMWPE in surgical implant application. Overall, melt-blending processing is more suitable for the preparation of UHMWPE/CNF bionanocomposites as exhibited by their characteristics presented herein. A better mechanical interlocking between UHMWPE and CNF at high temperature mixing with kneading was evident through FE-SEM observation, explains the higher mechanical properties of MB-UHMWPE/0.5 as compared to EM-UHMWPE/0.5.

scholarly journals Evaluation of Binders in Twin-Screw Wet Granulation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 241
Author(s):  
Claudia Köster ◽  
Sebastian Pohl ◽  
Peter Kleinebudde
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
Wet Granulation ◽  
Compression Pressure ◽  
Demineralized Water ◽  
Twin Screw

The binders povidone (Kollidon 30), copovidone (Kollidon VA64), hypromellose (Pharmacoat 606), and three types of hyprolose (HPC SSL-SFP, HPC SSL, and HPC SL-FP) were evaluated regarding their suitability in twin-screw wet granulation. Six mixtures of lactose and binder as well as lactose without binder were twin-screw granulated with demineralized water at different barrel fill levels and subsequently tableted. A screening run with HPC SSL determined the amount of water as an influential parameter for oversized agglomerates. Subsequent examination of different binders, especially Kollidon 30 and Kollidon VA64 resulted in large granules. All binders, except Pharmacoat 606, led to a reduction of fines compared to granulation without a binder. The molecular weight of applied hyproloses did not appear as influential. Tableting required an upstream sieving step to remove overlarge granules. Tableting was possible for all formulations at sufficient compression pressure. Most binders resulted in comparable tensile strengths, while Pharmacoat 606 led to lower and lactose without a binder to the lowest tensile strength. Tablets without a binder disintegrated easily, whereas binder containing tablets of sufficient tensile strength often nearly failed or failed the disintegration test. Especially tablets containing Pharmacoat 606 and HPC SL-FP disintegrated too slowly.

scholarly journals RICE STRAW/THERMOPLASTIC COMPOSITE: EFFECT OF FILLER LOADING, POLYMER TYPE AND MOISTURE ABSORPTION ON THE PERFORMANCE

CERNE ◽  
2016 ◽  
Vol 22 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Hossein Mohammadi ◽  
Seyedmohammad Mirmehdi ◽  
Lisiane Nunes Hugen
Keyword(s):  
Tensile Strength ◽  
Rice Straw ◽  
Moisture Absorption ◽  
Water Immersion ◽  
Filler Loading ◽  
Thermoplastic Composite ◽  
Modulus Of Rupture ◽  
Thermoplastic Composites ◽  
Composite Effect ◽  
Wet Condition

ABSTRAT Thermoplastic composites made with 45, 60 and 75% of rice straw as filler and two types of thermoplastics, virgin polyethylene (PE) and polypropylene (PP) were evaluated. The final boards were made with and without maleic anhydride modified polypropylene (MAPP) at 2% of the total weight of each specimen. The flexural and tensile strengths were measured for dry composites and also measured after 24 h of water immersion of the composites (wet condition). By increasing the filler content, the flexural and tensile strengths and also the density of the specimens decreased. The type of matrix (PE or PP) did not affect significantly the flexural strength, but PP led to higher values of tensile strength for low fiber loadings (45% and 60%). Coupling agents increased the flexural and tensile strength. After water immersion, modulus of elasticity and modulus of rupture were decreased, while tensile strength was less influenced.

Synthesis of Cyclic Polysulfides and their Properties as Curing Agents

2004 ◽  
Vol 77 (2) ◽  
pp. 380-390
Author(s):  
Wonmun Choi ◽  
Tomoyuki Matsumura
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
High Molecular Weight ◽  
Mass Spectra ◽  
Elongation At Break ◽  
Molecular Weights ◽  
Aging Properties ◽  
Curing Agents ◽  
Polysulfide Polymer

Abstract The reactions of dichloroalkanes and sodium tetra-sulfide (Na2S4) were carried out in a mixture of water and toluene to produce corresponding cyclic polysulfides and polysulfide polymer. The low molecular weights of cyclic sulfides were obtained by the reaction at 90 °C, while the high molecular weight of polysulfide polymer was obtained by the reaction at 50 °C. GPC chromatograms and Mass spectra revealed that the structures of cyclic polysulfide were 1:1, 2:2, and 3:3 adducts of dichloroalkane and sodium tetra-sulfide. The mechanical properties of vulcanized NR at 148 °C with cyclic sulfides were similar to that with sulfur. However, both tensile strength and elongation at break of vulcanized NR at 170 °C with cyclic sulfides are much higher than that with sulfur. The aging properties of vulcanized NR at 148 °C or 170 °C with cyclic polysulfides indicate better stability.

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