Wanyu Zhu

Amine-terminated nylon 6/66/1010 (AM-6/66/1010) used for hot melt adhesives: synthesis and properties

A new amine-terminated nylon 6/66/1010 (AM-6/66/1010) copolyamide hot melt adhesive with the molecular weight of 21,000–96,000 Da was synthesized and blocked with 1-hexadecylamine. The AM-6/66/1010 samples were characterized by 1H-NMR spectroscopy, differential scanning calorimetry (DSC), thermal gravimetric analysis, and gel permeation chromatography. The 1H-NMR spectroscopy demonstrated that 1-hexadecylamine functions as blocking agent in this polymerization. The DSC thermograms showed that the extra peak (peak (II)) and the melting peak (peak (I)) of AM-6/66/1010 are moving left and the glass transition temperature of AM-6/66/1010 decreases as the mole ratio αH/C (1-hexadecylamine/total carboxyl) increases. The thermal gravimetric analysis indicated that AM-6/66/1010 hot melt adhesive has a high thermal stability. The peel strength of the test specimen obtained by hot melt glutinous lining of AM-6/66/1010 or AC-6/66/1010 and fabric 6535 (65% PET, 35% cotton) was studied using T-peel tests, and the results showed that the washable and dry-cleaning resistant of AM-6/66/1010 copolyamide hot melt adhesive is better than that of carboxyl-terminated nylon 6/66/1010 (AC-6/66/1010) copolyamide hot melt adhesive.

Reactive hot melt polyurethane adhesives modified with pentaerythritol diacrylate: synthesis and properties

Abstract Pentaerythritol diacrylate (PEDA) was synthesized by direct esterification from acrylic acid and pentaerythritol, and the reactive hot melt polyurethane adhesives (PURs) with high green strength were prepared from Poly(1,6-hexamethyleneadipate), PHA-3000, two kinds of Poly(propylene glycol) (PPG-1000 and PPG-4000) and PEDA as well as terpene-phenolic resin. Five samples of PURs with different weight percent (α) of PEDA (α = 0, 3, 5, 7, and 10 wt%), were obtained. The rheological properties, thermal stability, and mechanical properties of the samples were investigated. The results showed that the melt viscosity (η) and the storage shear modulus of the samples increase with the increase in α, while the thermal stability changes little. The bonding strength of the samples after 10 min, 30 min, and 48 h was assessed by 180° peel tests of Fabric 6535/adhesives/Fabric 6535 stacks. The results showed that the green strength after 30 min increases with the increase in α when α is not higher than 7 wt%.

Synthesis and properties of polyamide/LLDPE composites with compatibilizer used as hot melt adhesive

Abstract In this work, a new polyamide (PA155) was synthesized from higher purity dimer acid, sebacic acid, ethylenediamine, and piperazine, and the ternary blends were prepared by blending PA155 with LLDPE in the presence of the compatibilizer, maleic anhydride grafted linear low-density polyethylene (LLDPE-g-MAH). The weight ratio of PA155 to LLDPE of the samples was kept constant at 80/20 and the amount of LLDPE-g-MAH was varied at 0, 3, 6, 9, and 12 wt% over the total weight of the blend respectively. The scanning electron microscope and mechanical properties tests showed that the compatibility and the mechanical properties were improved with the increase in LLDPE-g-MAH content, and the blend containing 9.0 wt% LLDPE-g-MAH exhibits an optimal miscibility behavior and mechanical properties. The hot melt adhesives which were prepared from the ternary blends were assessed by 180°peel tests of Al/adhesive/polypropylene stack. The peeling strength for the sample containing 9.0 wt% compatibilizer (82.5 N/2.5 cm) is much more than that of the samples without compatibilizer (<20 N/2.5 cm).

Synthesis and properties of modified PBT for FDM

Purpose The purpose of this paper is to prepare a new modified polybutylene terephalate (MPBT) for fused deposition modeling (FDM) to increase the variety of materials compatible with printing. And the printing materials can be used to print components with a complex structure and functional mechanical parts. Design/methodology/approach The MPBT, poly(butylene terephalate-co-isophthalate-co-sebacate) (PBTIS), was prepared for FDM by direct esterification and subsequent polycondensation using terephthalic acid (PTA), isophthalic acid (PIA), sebacic acid (SA) and 1,4-butanediol (BDO). The effects of the content of PIA (20-40 mol%) on the mechanical properties of PBTIS were investigated when the mole per cent of SA (αSA) is zero. The effects of αSA (0-7mol%) on the thermal, rheological and mechanical properties of PBTIS were investigated at nPTA/nPIA = 7/3. A desktop wire drawing and extruding machine was used to fabricate the filaments, whose printability and anisotropy were tested by three-dimensional (3D) printing experiments. Findings A candidate content of PIA introducing into PBT was obtained to be about 30 per cent, and the Izod notched impact strength of PBTIS increased with the increase of αSA. The results showed that the PBTIS (nPTA/nPIA = 7/3, αSA = 3-5mol%) is suitable for FDM. Originality/value New printing materials with good Izod notched impact strength were obtained by introducing PIA and SA (nPTA/nPIA = 7/3, αSA = 3-5 mol%) into PBT and their anisotropy are better than that of ABS.

Hot melt adhesive properties of PA/TPU blends compatibilized by EVA-g-MAH

Abstract A new copolyamide (PA52) with good adhesion to aluminum (Al) sheets was synthesized from caprolactam, nylon 66 salt, nylon 1010 salt, and stearic acid, and a series of PA52/TPU blends compatibilized by maleic anhydride-grafted ethylene vinyl acetate (EVA-g-MAH) were prepared for use as hot melt adhesives. In the ternary blends (PA52/EVA-g-MAH/TPU), the weight ratio of PA52 to TPU was kept constant at 50/50 and the amount of EVA-g-MAH was varied at 0, 2, 4, 6, and 8 wt% over the total weight of the blend, respectively. The solubility parameters were taken into account to describe the partial compatibility of PA52/TPU blends. The effects of EVA-g-MAH content on the melt viscosity, morphology, mechanical and thermal properties of ternary blends were systematically investigated, and the adhesion strength of hot melt adhesives based on the ternary blends were determined in terms of 90° peeling strength tests of Al/adhesive/ABS stacks. The results showed that the melt viscosity of ternary blends were greater than that of PA52/TPU blend, and the blend containing 6 wt% EVA-g-MAH exhibited an optimal miscibility behavior and excellent mechanical properties, at the same time, its peeling strength reached the maximum (120 N/25 mm).