Hydroxypropylation Reduces Gelatinization Temperature of Corn Starch for Textile Sizing

Abstract A series of hydroxypropylated starch (HPS) that can be dissolved in water at 60-65℃ was obtained via two-step method in water system from corn starch. The structure and property of the HPS and its gelatinization temperature were characterized by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectroscopy ( 1 H NMR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and transmission electron microscope (TEM). It was concluded that hydroxypropyl mainly bonded on the hydroxyl group at C 2 position from anhydroglucose unit of starch in the form of C-O-C, and the substitution level at C 6 position was slightly higher than that at C 3 position; and the crystallinity of starch decreased from 52.41% to 29.4% due to the introduction of hydroxypropyl and was confirmed by XRD. At the same time, the grooves on the surface of starch granules were observed by SEM. The above-mentioned two synergism promoted the permeation and transmission of water molecules in the starch microstructure. Moreover, the gelatinization temperatures and enthalpy of synthetic HPS was lower than that of raw corn starch, as further confirmed by DSC. This caused the HPS with a molar substitution greater than 0.1 soluble in water at 65℃, and the dissolution state was similar to that of at 95℃ (transmittance above 55%), as well as exhibited high slurry stability. Interestingly, compared with the raw starch, the HPS film showed excellent mechanical property at the relative humidity of 65%, which could be attributed to the hydrophilic ether bond and the flexible alkyl chain bonded on the structure of starch. This study will provide a new way for the preparation of high performance starch size for sizing yarn at medium low temperature.

Download Full-text

Semi-Interpenetrating Polymer Networks Based on Cyanate Ester and Highly Soluble Thermoplastic Polyimide

Polymers ◽

10.3390/polym11050862 ◽

2019 ◽

Vol 11 (5) ◽

pp. 862 ◽

Cited By ~ 8

Author(s):

Jingfeng Liu ◽

Weifeng Fan ◽

Gewu Lu ◽

Defeng Zhou ◽

Zhen Wang ◽

...

Keyword(s):

High Performance ◽

Elevated Temperatures ◽

Polymer Networks ◽

Gelation Time ◽

Interpenetrating Polymer Networks ◽

Step Method ◽

Scanning Calorimetry ◽

Sem Images ◽

Biphenyltetracarboxylic Dianhydride ◽

The Impact

Thermoplastic polyimide (TPI) was synthesized via a traditional one-step method using 2,3,3′,4′-biphenyltetracarboxylic dianhydride (3,4′-BPDA), 4,4′-oxydianiline (4,4′-ODA), and 2,2′-bis(trifluoromethyl)benzidine (TFMB) as the monomers. A series of semi-interpenetrating polymer networks (semi-IPNs) were produced by dissolving TPI in bisphenol A dicyanate (BADCy), followed by curing at elevated temperatures. The curing reactions of BADCy were accelerated by TPI in the blends, reflected by lower curing temperatures and shorter gelation time determined by differential scanning calorimetry (DSC) and rheological measurements. As evidenced by scanning electron microscopy (SEM) images, phase separation occurred and continuous TPI phases were formed in semi-IPNs with a TPI content of 15% and 20%. The properties of semi-IPNs were systematically investigated according to their glass transition temperatures (Tg), thermo-oxidative stability, and dielectric and mechanical properties. The results revealed that these semi-IPNs possessed improved mechanical and dielectric properties compared with pure polycyanurate. Notably, the impact strength of semi-IPNs was 47%–320% greater than that of polycyanurate. Meanwhile, semi-IPNs maintained comparable or even slightly higher thermal resistance in comparison with polycyanurate. The favorable processability and material properties make TPI/BADCy blends promising matrix resins for high-performance composites and adhesives.

Download Full-text

Heat-resistant and photoluminescent indole-based poly(ether sulfone)s

High Performance Polymers ◽

10.1177/0954008317701823 ◽

2017 ◽

Vol 30 (4) ◽

pp. 475-479 ◽

Cited By ~ 5

Author(s):

Wenxuan Wei ◽

Li Yang ◽

Guanjun Chang

Keyword(s):

Thermal Stability ◽

High Performance ◽

Proton Nuclear Magnetic Resonance ◽

Resonance Spectroscopy ◽

Condensation Polymerization ◽

High Glass Transition Temperature ◽

Scanning Calorimetry ◽

Good Thermal Stability ◽

High Performance Polymers ◽

Good Agreement

Indole-based poly(ether sulfone)s (PINESs), as novel high-performance polymers, have been obtained by the condensation polymerization of 4-hydroxyindole and hydroquinone with activated difluoro monomers via a catalyst-free nucleophilic substitution reaction. The structures of the polymers are characterized by means of Fourier transform infrared and proton nuclear magnetic resonance spectroscopy, and the results show good agreement with the proposed structures. Differential scanning calorimetry and thermogravimetric analysis measurements exhibit that polymers possess high glass transition temperature ( Tgs > 245°C) and good thermal stability with high decomposition temperatures ( Tds > 440°C). In addition, due to their special structure, PINESs are endowed with significantly strong photonic luminescence in N, N-dimethylformamide.

Download Full-text

Corrosion Resistance of Mild Steel Coated with Phthalimide-Functionalized Polybenzoxazines

Coatings ◽

10.3390/coatings10111114 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1114

Author(s):

Kamal I. Aly ◽

Abdulsalam Mahdy ◽

Mohamed A. Hegazy ◽

Nayef S. Al-Muaikel ◽

Shiao-Wei Kuo ◽

...

Keyword(s):

Corrosion Resistance ◽

Mild Steel ◽

High Performance ◽

Functional Group ◽

Curing Temperature ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Mannich Reactions ◽

Polymerization Behavior ◽

Thermal Stability Of

Herein, we synthesized two new phthalimide-functionalized benzoxazine monomers, pPP-BZ and oPP-BZ, through Mannich reactions of 2-(4-hydroxyphenyl)isoindoline-1,3-dione (pPP) and 2-(2-hydroxyphenyl)isoindoline-1,3-dione (oPP), respectively, with p-toluidine and paraformaldehyde. The structures of these two monomers were confirmed using Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopy. We used differential scanning calorimetry, FTIR spectroscopy, and thermogravimetric analysis to study the polymerization behavior and thermal stability of the monomers and their corresponding polybenzoxazines. Poly(pPP-BZ) and poly(oPP-BZ) were formed on mild steel (MS) through spin-coating and subsequent thermal curing polymerization. We used various corrosion testing methods to examine the effect of the curing temperature on the corrosion resistance of the coated MS samples in 3.5 wt.% aqueous solution of NaCl. Among our tested systems, the corrosion rate reached a low of 2.78 µm·Y−1 for the MS coated with poly(pPP-BZ)180 (i.e., the coating that had been cured at 180 °C); this value is much lower than that (4.8 µm·Y−1) reported for a maleimide-based benzoxazine compound (MI-Bz)/33 wt.% ACAT (amine-capped aniline trimer) blend. Thus, the incorporation of the imide functional group into the PBZ coatings is an effective strategy for affording high-performance corrosion resistance.

Download Full-text

Thermal behaviour of benzoxazine blends based on epoxy and cyanate ester

Polymers and Polymer Composites ◽

10.1177/09673911211059714 ◽

2021 ◽

Vol 29 (9_suppl) ◽

pp. S1475-S1485

Author(s):

Balaji Krishnasamy ◽

Hariharan Arumugam ◽

Mohamed Iqbal M ◽

Alagar Muthukaruppan

Keyword(s):

High Performance ◽

Analytical Techniques ◽

Cyanate Ester ◽

Resonance Spectroscopy ◽

Scanning Calorimetry ◽

Limiting Oxygen Index ◽

Polymeric Matrices ◽

Bisphenol F ◽

Degradation Temperature ◽

Cure Behaviour

In the present work, an attempt has been made to develop high-performance polymeric hybrid binary blends of epoxy/benzoxazine and benzoxazine/cyanate ester with varying weight percentages (25/75, 50/50 and 75/25 wt%) of resins, namely, bisphenol-F epoxy resin (DGEBF), benzoxazines [bisphenol–F/aniline (BF-a) and imidazole core-based bisphenol/aniline (IBP-a)] and cyanate ester [bisphenol-F bifunctional cyanate ester (BF-CE)]. The molecular structure, polymerisation temperature/cure behaviour, glass transition temperature (Tg) and thermal stability of the neat polymeric matrices and binary hybrid blends of polymeric matrices were characterised using different analytical techniques, viz. Fourier Transform infra-red spectroscopy (FTIR), Nuclear Magnetic Resonance spectroscopy (NMR), Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA). Among the binary hybrid blends, the lowest polymerisation temperatures (Tp) were noticed in the case of blends of epoxy/benzoxazine were 219°C for DGEBF/BF-a (25/75 wt%) and 170°C for DGEBF/IBP-a (25/75 wt%). Similarly, in the case of blends of benzoxazine/cyanate ester, the lowest values of Tp observed were 155°C and 153°C for BF-a/BF-CE (75/25 wt%) and IBP-a/BF-CE (75/25 wt%), respectively. The highest values of Tg observed for the blends of epoxy/benzoxazine were 175°C and 254°C for DGEBF/BF-a (25/75 wt%) and DGEBF/IBP-a (25/75 wt%), respectively. Whereas, the highest values of Tg observed in the case of blends of benzoxazine/cyanate ester were 234°C and 278°C for BF-a/BF-CE (25/75 wt%) and IBP-a/BF-CE (75/25 wt%), respectively. From the TGA results of blends, the maximum degradation temperature (Tmax) and limiting oxygen index (LOI) value calculated from the char yield, which ascertain that almost all the binary hybrid blends of epoxy/benzoxazine and benzoxazine/cyanate ester possess good flame retardant behaviour.

Download Full-text

Effects of preincubation on the gelatinization of cassava and corn starch suspensions containing sodium hydroxide as a main component of corrugating adhesives

TAPPI Journal ◽

10.32964/tj18.5.321 ◽

2019 ◽

Vol 18 (5) ◽

pp. 321-329

Author(s):

TAKATOSHI KOYAKUMARU ◽

HIROFUMI NAKANO

Keyword(s):

Sodium Hydroxide ◽

Corn Starch ◽

Cassava Starch ◽

Molar Ratio ◽

Starch Granules ◽

Gelatinization Temperature ◽

Scanning Calorimetry ◽

Long Time ◽

C 50 ◽

Main Component

Effects of the preincubation temperature and the caustic-ratio, the molar ratio of sodium hydroxide to starch glucose residue, on the gelatinization of cassava starch and corn starch suspensions were studied using differential scanning calorimetry in view of utilization for corrugating adhesives. The gelatinization temperature and enthalpy change of cassava starch suspensions after the preincubation at 30°C decreased as the caustic-ratio increased, similar to those of corn starch ones: The gelatinization starting temperature (Ts) decreased considerably more than the peak temperature and the conclusion temperature (Tc). Although Ts lowered and the width of gelatinization temperature expanded, compared with those of corn starch suspensions, the two starch suspensions with the same half gelatinization transition temperature showed similar gelatinization characteristics of almost the same Ts and Tc. During 1 h-preincubations at 30°C–50°C, the starch granules with Ts that were lowered considerably below each preincubation temperature by sodium hydroxide showed limited gelatinization. The gelatinization transition did not rapidly spread over the whole suspension, but progressed stepwise in response to the increase of the causticratio and the rise of the preincubation temperature. In a prolonged preincubation at a constant temperature, Ts gradually rose at higher caustic-ratios in which stepwise gelatinization commenced. Although the starch gelatinization was irreversible and not in a stable equilibrium state for a long time, we concluded that such stepwise gelatinization progress controlled the practical preparation and use of corrugating adhesives.

Download Full-text

A high performance polybenzoxazine via smart ortho-norbornene functional benzoxazine monomer based on ring-opening metathesis polymerization

High Performance Polymers ◽

10.1177/0954008318780995 ◽

2018 ◽

Vol 31 (5) ◽

pp. 513-520 ◽

Cited By ~ 3

Author(s):

Kan Zhang ◽

Yuqi Liu ◽

Yuting Wang ◽

Lin Sun

Keyword(s):

Molecular Weight ◽

Ring Opening ◽

High Performance ◽

Average Molecular Weight ◽

Side Chain ◽

Resonance Spectroscopy ◽

Thermal Curing ◽

Ring Opening Metathesis Polymerization ◽

Scanning Calorimetry ◽

Metathesis Polymerization

Monofunctional benzoxazine with ortho-norbornene functionality ( oHPNI-a) has been synthesized via Mannich condensation. The benzoxazine monomer containing norbornene group can be polymerized by ring-opening metathesis polymerization (ROMP) to form a side-chain benzoxazine functionalized polynorbornene (poly( oHPNI-a)side) with number-average molecular weight 3840 and weight-average molecular weight 7290. The structures of synthesized monomer and side-chain functionalized linear polymer have been confirmed by 1H nuclear magnetic resonance spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The further thermal curing polymerization mechanisms of poly( oHPNI-a)side are monitored by in situ FTIR and differential scanning calorimetry (DSC). Activation energy of polymerization for poly( oHPNI-a)side is also studied by DSC. The polybenzoxazine obtained by ROMP and further thermally activated ring-opening polymerization exhibits much higher thermal stability than the polybenzoxazine directly formed by traditional thermal curing.

Download Full-text

Rapid Estimation of Parameters for Gelatinization of Waxy Corn Starch

Foods ◽

10.3390/foods8110556 ◽

2019 ◽

Vol 8 (11) ◽

pp. 556

Author(s):

Robert Bertrand ◽

William Holmes ◽

Cory Orgeron ◽

Carl McIntyre ◽

Rafael Hernandez ◽

...

Keyword(s):

Corn Starch ◽

Rapid Determination ◽

Thermal Characteristics ◽

Gelatinization Temperature ◽

Estimation Of Parameters ◽

Scanning Calorimetry ◽

Starch Gelatinization ◽

Waxy Corn Starch ◽

Waxy Corn

Starch gelatinization is an important process due to the prevalence of starch usage in industries such as cosmetics and food production. In this study, the gelatinization of waxy corn starch (WCS) was investigated with the goal of providing an option for the rapid determination of starch gelatinization characteristics. The procedure used in the study was solely based on differential scanning calorimetry (DSC), which is an established technique for the determination of thermal characteristics of starches. A sequence of experiments was conducted to determine the excess water condition, an estimate of the minimum gelatinization temperature, and gelatinization time. These parameters were found to be ≥65 wt.% water, 75–85 °C, and 10 min, respectively. The estimation of the minimum gelatinization temperature was determined from the thermal properties of the WCS as obtained by DSC. The obtained parameters resulted in complete WCS gelatinization, and, thus, the sequence of procedures used in the study could possibly be used for rapid waxy starch evaluation.

Download Full-text

Superionic Lithium Intercalation through 2 nm x 2 nm Columns in the Crystallographic Shear Phase Nb18W8O69

10.26434/chemrxiv.11231153.v1 ◽

2019 ◽

Author(s):

Kent Griffith ◽

Clare Grey

Keyword(s):

High Performance ◽

Rate Capability ◽

Block Size ◽

Lithium Intercalation ◽

Resonance Spectroscopy ◽

Complex Metal Oxides ◽

Battery Electrode ◽

Crystallographic Shear ◽

Battery Material ◽

First Time

Nb18W8O69 (9Nb2O5×8WO3) is the tungsten-rich end-member of the Wadsley–Roth crystallographic shear (cs) structures within the Nb2O5–WO3 series. It has the largest block size of any known, stable Wadsley–Roth phase, comprising 5 ´ 5 units of corner-shared MO6 octahedra between the shear planes, giving rise to 2 nm ´ 2 nm blocks. Rapid lithium intercalation is observed in this new candidate battery material and 7Li pulsed field gradient nuclear magnetic resonance spectroscopy – measured in a battery electrode for the first time at room temperature – reveals superionic lithium conductivity. In addition to its promising rate capability, Nb18W8O69 adds a piece to the larger picture of our understanding of high-performance Wadsley–Roth complex metal oxides.

Download Full-text

Star-shaped arylacetylene resins derived from silicon

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0083 ◽

2020 ◽

Vol 40 (8) ◽

pp. 676-684

Author(s):

Niping Dai ◽

Junkun Tang ◽

Manping Ma ◽

Xiaotian Liu ◽

Chuan Li ◽

...

Keyword(s):

High Performance ◽

Room Temperature ◽

Mechanical Test ◽

Flexural Modulus ◽

Mechanical Analysis ◽

Reinforced Composites ◽

Scanning Calorimetry ◽

Chemical Structures ◽

Structures And Properties ◽

High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

Download Full-text

Effect of Nanofiller Content on Dynamic Mechanical and Thermal Properties of Multi-Walled Carbon Nanotube and Montmorillonite Nanoclay Filler Hybrid Shape Memory Epoxy Composites

Polymers ◽

10.3390/polym13050700 ◽

2021 ◽

Vol 13 (5) ◽

pp. 700

Author(s):

Muhamad Hasfanizam Mat Yazik ◽

Mohamed Thariq Hameed Sultan ◽

Mohammad Jawaid ◽

Abd Rahim Abu Talib ◽

Norkhairunnisa Mazlan ◽

...

Keyword(s):

Shape Memory ◽

High Performance ◽

Loss Modulus ◽

Decomposition Temperature ◽

Hybrid Nanocomposites ◽

Mechanical And Thermal Properties ◽

Scanning Calorimetry ◽

Hybrid Filler ◽

Dynamic Mechanical ◽

Tan Δ

The aim of the present study has been to evaluate the effect of hybridization of montmorillonite (MMT) and multi-walled carbon nanotubes (MWCNT) on the thermal and viscoelastic properties of shape memory epoxy polymer (SMEP) nanocomposites. In this study, ultra-sonication was utilized to disperse 1%, 3%, and 5% MMT in combination with 0.5%, 1%, and 1.5% MWCNT into the epoxy system. The fabricated SMEP hybrid nanocomposites were characterized via differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The storage modulus (E’), loss modulus (E”), tan δ, decomposition temperature, and decomposition rate, varied upon the addition of the fillers. Tan δ indicated a reduction of glass transition temperature (Tg) for all the hybrid SMEP nanocomposites. 3% MMT/1% MWCNT displayed best overall performance compared to other hybrid filler concentrations and indicated a better mechanical property compared to neat SMEP. These findings open a way to develop novel high-performance composites for various potential applications, such as morphing structures and actuators, as well as biomedical devices.

Download Full-text