Reaction Injection Molding Research Articles

Influence of the Reaction Injection Moulding Process on the Thermomechanical Behaviour of Fast Curing Polyurethane

In this contribution, the influence of the reaction injection moulding process on the thermomechanical material behaviour of aliphatic hexamethylene diisocyanate (HDI) based fast curing polyurethane is demonstrated. Uniaxial tensile tests, temperature-frequency dependent dynamic mechanical thermal analysis (DMTA) and Differential Scanning Calorimetry (DSC) are used to show the differences in properties for ten different sets of process parameters. The mould and resin components temperature, the mass flow during the filling process and the residence time during the reaction process of the polyurethane are varied in several stages. Further experiments to determine the molar mass of the molecular chain between two crosslinking points of the polyurethane are used to explain the process influences on the thermomechanical properties. Thus, a direct correlation between manufacturing and material properties is shown. In addition, the mutual effect of the different parameters and their overall influence on the material behaviour is presented.

Rheokinematics for product development—Formulation screening in rotational rheometers

AbstractProduct formulations for industrial processes are typically developed at laboratory scale. However, the mixing conditions are not easily mimicked in the laboratory. A rotational device is proposed in this study as a fast laboratory‐scale formulation development, which enables mimicking the mixing conditions in the industrial process. The geometrical configurations of the rotational device are from rheometry devices (plate‐plate and cone‐plate). The main advantages of this method are the small amounts of raw materials and shorter testing times. This methodology is applied to an industrial case study, the reaction injection molding (RIM) process. The mixing length scales evolution in the rotational rheometer were matched to those in RIM machines. The main novelty of this study is the introduction of a protocol that bridges the processing conditions at laboratory using small amounts of raw materials to high throughput continuous flow reactors.

Quasi-Static and Fatigue Properties of Thermoset Sandwiches with 3D Continuous Fibre Reinforced Polyurethane Foam Core.

Innovative materials for substituting metals are required to reduce the mass of moving components. This decreases the CO2 emissions of overall systems. A thermoset sandwich for high mechanical properties and thermal insulation is presented in this paper. It has an innovative 3D continuous reinforced core, which allows the optimisation of the substance exploitation by wide-ranging possibilities of fibre orientation. This was demonstrated with three sandwich variants. The reference had no core reinforcement and the other two were reinforced with different spacer fabrics. The process chain for the manufacturing consists of Structural Reaction Injection Moulding (SRIM) and Vacuum Assisted Resin Transfer Moulding (VARTM). Significant increases in absolute as well as specific characteristic values were demonstrated by the reinforcement in a compression and bending test. It was also shown that quasi-static characteristic values under fatigue loading are maintained to a greater extent with the core reinforcement. The sandwich material was applied as a floor assembly for a snow groomer. The design was tailor-made for the mechanical, thermal and acoustic requirements. This proved the transferability of the process chain for manufacturing samples to the production of large-volume components with complex geometry.

Numerical simulation with experimental validation of the structural reaction injection moulding of 3D continuous fibre reinforced polyurethane foam

Sandwich composite materials are established in the industry. Polyurethane foam reinforced with spacer fabric represents an innovative solution for a core in this field. It is manufactured in the Structural Reaction Injection Moulding (SRIM). This paper describes new investigations that provide the base for component and process design when using this Interpenetrating Phase Composite (IPC). Filling studies were carried out for this purpose in three moulding tools with different cavities with and without spacer fabric. It is shown that the PUR foam expansion and the foam bulk density are clearly influenced by the sprue type, cavity design and spacer fabric. Simulations are necessary to investigate all process-structure-property relationships in detail and to enable a user-friendly and efficient design of material and process. Adequate mathematical models to simulate the transport of mass, heat and momentum in the SRIM are presented in this paper. The resistance to the expansion process caused by the porous structures in the domain were taken into account. The transport of momentum in the mould is described with the Navier–Stokes-Brinkman equations which in the limit of the permeability tensor reduces to the Navier–Stokes equation. The model equations are solved numerically and the results show reasonable agreement with the experimental data.

Laser Optoacoustic Method for Quantitative Estimation of Porosity in Cast Dispersion-Strengthened Metal-Matrix Composite Materials

A laser optoacoustic method for quantitative assessment of the volumetric porosity of cast dispersion-strengthened metal-matrix composite materials has been proposed and experimentally implemented. The method is based on a statistical analysis of the distribution of amplitudes of backscattered broadband pulses of longitudinal acoustic waves in the tested materials. Laser excitation and piezoelectric recording of ultrasound is implemented with one-way access to the test object using a special laser-ultrasonic transducer. Silumin-based composites reinforced with silicon carbide microparticles in various volume concentrations (0.033–0.135) and composites obtained by reaction injection moulding based on aluminum reinforced with intermetallic $${\text{A}}{{{\text{l}}}_{3}}{\text{Ti}}$$ (volume concentration 0.04–0.115) have been studied. For both types of composites, the distribution of amplitudes of backscattered ultrasonic signals is approximated by a Gaussian distribution function applicable for a large number of statistically independent quantities. The empirically obtained dependence of the half-width of this distribution on the volumetric porosity of composites of two different types is approximated by the same linear function regardless of the manufacturing technology, as well as of the type, size, and concentration of strengthening particles.

Post-Polymerization Heat Effect in the Production of Polyamide 6 by Bulk Quasiliving Anionic Ring-Opening Polymerization of ε-Caprolactam with Industrial Components: A Green Processing Technique

Bulk, solventless anionic ring-opening polymerization (AROP) of ε-caprolactam (CPL) with high yields, without side products and with short reaction times, initiated by caprolactamate-carbamoylcaprolactam initiating systems belong to green polymerization processes, leading to poly(ε-caprolactam) (Polyamide 6, PA6, Nylon 6). However, the effect of post-polymerization heat (i.e., slow, technically feasible cooling) on the fundamental characteristics of the resulting polymers such as yield and molecular weight distributions (MWDs) have not been revealed thus far. Significant post-polymerization effect was found by us in terms of both monomer conversions and MWDs by carrying out CPL polymerization with industrial components under conditions mimicking thermoplastic reaction transfer molding (T-RTM). Remarkably, higher monomer conversions and molecular weights (MWs) were obtained for Polyamide 6 samples prepared without quenching than that for the quenched polymers at the same reaction times. Independent of quenching or non-quenching, Mn of the resulting polymers as a function of conversion fell in the theoretical line of quasiliving AROP of CPL. At high monomer conversions, significant increase of the MW and broadening of the MWDs occurred, indicating pronounced chain–chain coupling. These findings have fundamental importance for designing processing conditions for in situ polymerization processes of ε-caprolactam by various techniques such as T-RTM, reaction injection molding (RIM), and other processing methods of Polyamide 6.

Design of a twill pattern jute fiber composite pressure vessel

Pressure Vessels are commonly used equipment that is used in so many applications. From time to time, these vessels are developed in so many manners like material replaceblity, application changes, cost bases, and environmental aspects. Due to the highest demand in the market day by day, the materials of the pressure vessel was changed for reducing weight, improve mechanical properties, cost basis, and lifetime, etc. Nowadays the commonly used materials in composites are Glass, Carbon, and Aramid fibers. Basically in composites, the method used for manufacturing pressure vessels is the Filament winding process. There are so many methods are there like Bag Molding, Hand Lay-up, Open molding, Resin infusion processes, Reaction injection molding (RIM), Vacuum-assisted resin transfer molding (VARTM), etc. In this Paper the Pressure Vessel Was Made up of with Jute fiber twill pattern cloth, Epoxy Resin, and intermediate material was raw jute and the method used for manufacturing is Hand Lay-up technique. Jute is the easily available material and the cost is also less as compared with synthetic fibers. The main advantage of the natural fiber (Jute) is it is easily degradable material. This Pressure vessel was made with the help of the ASME SECTION-X Handbook. As compared to glass fiber Pressure vessel the thickness of jute fiber pressure vessel is high and Burst pressure also 50% less. Compared with glass fiber jute is the cheapest material.

Polymeric hollow fibers: A supercompact cooling of Li-ion cells

An unconventional design of the heat exchanger has been introduced for conventional liquid cooled systems of battery modules/packs of electric vehicles (EVs). It is deemed unconventional, because only non-metallic materials are used, namely polydicyclopentadiene (PDCPD) as a mechanical housing and polymeric hollow fibers as coolant channels. The heat exchanger is lightweight, electrically non-conductive, durable, wear resistant, low cost, manufacturable. Very small in diameter (<1 mm), the fibers were woven in a specific manner around a number of cylindrical Li-ion cells 18650. After that, the fibers' position was fixed in PDCPD processed during the reaction injection molding (RIM). In this study, the cooling performance of the heat exchanger was examined both numerically and in experiments. The findings of both approaches concur with each other. From the perspective of temperature homogeneity, the current prototype shows acceptable performance when compared to the standard exchangers on the market. The results presented show further room for promising design modifications.

Production and Dynamic Mechanical Analysis of Macro-Scale Functionalized Polydicyclopentadiene Objects Facilitated by Rational Synthesis and Reaction Injection Molding

Polydicyclopentadiene (PDCPD) is a ring-opening metathesis polymer derived from dicyclopentadiene. Valued for its light weight, excellent material strength, and good performance at both high and low temperatures, PDCPD is used to make body panels for tractors and heavy-duty trucks. We recently described the first functionalized form of PDCPD (fPDCPD) that maintains the thermal stability of the parent polymer. However, while commercial PDCPD components are produced through a reaction injection molding process on a very large scale, our fPDCPD polymer was developed on a small scale and has not been shown to be a viable substrate for reaction injection molding processes. Here we address these limitations by providing an improved synthesis of the fDCPD monomer mixture on a half-kilo scale and describing a method for separating the polymerizable monomer from other nonpolymerizable regioisomers without chromatography. We further demonstrate a reaction injection molding process for the creation of prototype fPDCPD components. Together, these increases in scale and advances in small object manufacturing facilitate the production of regular-dimensioned samples for dynamic mechanical analysis, permitting the first direct comparison of the mechanical properties of C-linked ester-functionalized PDCPD with those of unmodified PDCPD. Additionally, by using monomers of different regioisomer purity, products are achieved encompassing a broad range of glass transition temperatures and storage/loss moduli.

Lightweight Potential of 3D Endless Fiber Reinforcement of Polyurethane Foam Cores with Spacer Fabrics in Hybrid Sandwich Structures with Fiber Reinforced Thermoplastic Facings

Sandwich structures consisting of fibre-reinforced plastic (FRP) facings and core are ideally suited as substitution materials for reducing component masses. The endless fibre reinforcement has the greatest performance potential. Both thermoset and thermoplastics are already being processed into endless fibre-reinforced sandwich facings according to the state of the art. The 3D endless fibre reinforcement of cores is a current research topic. This paper describes the development of a hybrid sandwich consisting of thermoplastic composite facings and an innovative core composite. This is made of polyurethane (PUR) rigid or flexible foam, which is reinforced with spacer fabric. The sandwich manufacturing in Reaction Injection Moulding (RIM) includes the original forming of the core and the simultaneous bonding of the facings. This efficient process offers the potential for the production of such complex structures in medium or large series. The sandwich structures and their individual components were characterised in the standardised compression and bending test. The lightweight potential of spacer fabric reinforcement is demonstrated by comparing the specific mechanical properties of sandwich structures with and without core reinforcement. In comparison to reinforced and unreinforced foams, the effect of sandwich design is also shown.

Preparation and in vitro/in vivo evaluation of anastrozole reservoir-type intravaginal ring.

This report details the preparation of anastrozole (ATZ) reservoir-type intravaginal ring (IVR) and the detection of the concentration of ATZ in beagle dog plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS). An ATZ reservoir-type IVR which included ATZ silicone elastomer core and a nonactive silicone layer was manufactured by reaction injection moulding at 80°C for 20 min. An in vitro release experiment was performed under sink conditions and the samples were determined by high-performance liquid chromatography. A bioanalytical method was developed and validated for determination of ATZ in beagle dog plasma for IVR development. The analytical method consisted of the extraction of plasma samples and determination of ATZ by LC-MS/MS using buspirone as the internal standard. Separation was achieved on a Kinetex-C18 110A column (3 × 30 mm, 2.6 μm, Phenomenex) using step-gradient mobile phase and an isocratic flow rate consisting of formic acid. Protonated ions formed by a turboion spray in the positive mode was used to detect the analyte (ATZ) and internal standard. The MS-MS detection was performed on a triple quadrupole mass spectrometer equipped with electrospray ionization source. The mass spectrometer was operated in the multiple reaction monitoring mode. The mass transition ion-pair was followed as m/z from 294.10 to 225.08 for anastrozole and m/z from 386.23 to 122.11 for buspirone. The results proved that the correlation between in vitro and in vivo analyses was relatively good.

Data encoding and reconstruction of thermal imaging maps of impact damaged composite Structures using feature space and neural networks

A new approach to characterizing and predicting impact damage level in (Reaction Injection Molding) RIM structures is presented. The technique encodes thermal images maps and extracts features from presented thermal images. Complex Neural Networks structure is employed to reconstruct thermal imaging maps and predict the extent of damage an impact can cause. Neural network weigh elimination algorithm is used and proved effective in predicting areas of damage.

Effect of Correlating ImageThreshold Values with Image Gradient Field on Damage Detection in Composite Structures

Effect of image threshold level variation is studied and proved to be a critical factor in damage detection and characterization of impacted composite Reaction Injection Molding ((RIM) structures. The variation of threshold is used as an input to both gradient field algorithm and segmentation algorithm. The choice of optimum threshold for a tested composite type is achieved as a result of correlation between the resulted gradient field images and segmented images. Type and extent of damage is also analyzed using detailed pixel distribution as a function of both impact energy and threshold level variation. The demonstrated cascading based technique is shown to be promising for an accurate testing and classification of damage in composite structures in many critical areas such as medical, aerospace and automotive.

Textile-based surface design of thermoplastic composites for microstructural adhesion to polyurethane foams for lightweight structures

ABSTRACTIn an effort to reduce the mass of components, sandwich design has become well established above all in the aerospace and the vehicle construction. In these structures, facings and cores made of very different materials are joined using a wide variety of technologies. The challenge in the use of this type of construction frequently results both from generating component joints stable enough to bear loads and the productivity of the manufacturing process. This publication investigates the textile-based surface design of thermoplastic composites which create optimised conditions for the bonding of Polyurethane (PUR) foam cores in the in-situ foaming. The reinforcement layer structure is represented on the surface by varying the layer stack in the production of textile-based thermoplastic composites through pressing. This approach is resource and energy-efficiency because it includes no additional process steps. Two thermoplastic composite variants with differently firmed textile surface structure were manufactured and analysed. In reaction injection moulding, each variant was processed with two different PUR foam cores to obtain sandwich structures. Bonding between the facings and the core was only achieved by means of textile microstructuring, which was demonstrated in the analysis of the basic materials and the microstructure penetration through PUR foam as well. The mechanical capacity of the interface was determined by the sandwich structures in the tensile test. In future studies, a bulky, textile-based lightweight construction material in sandwich design that is both suitable for application and capable of being mass produced will be developed based on these investigations.

Characterization of Composite Structure Surface Uniformity using Interval Based Gradient Field Histogram Analysis of Thermographic Images (IGF-HA)

This paper presents a new approach to composite surface characterization using Image Histogram Analysis as a function of Gradient Field. Image sequences are weighed and combined in order to present a pattern change in the thermal response of a tested composite structure. Reaction Injection Molding samples used and subjected to thermal energy to characterize their surface uniformity and any existing damage. A threshold value is used for the purpose of segmenting and separating damaged from undamaged areas in the tested composite structure. Gradient field analysis established the critical time at which the surface started to show damage and segmented the tested images into areas of concern. The resulting histograms cover four main regions of interest according to the gradient intensities as a function of time. Each region is divided into eight subsections according to the corresponding limit value, resulting in thirty two subsections. Correlation between region gradient field and its histogram resulted in uncovering of surface deformities as a function of surface area thermal storage. The process is modeled mathematically.

Poly-DCPD형 복합에폭시수지의 무기물 충전재별 특성에 관한 연구

Poly-DCPD type epoxy resin and composite materials were prepared reaction injection molding(RIM) polymerization from polyamide based curing agents(G-5022:G-0930) with inorganic filler(SiO₂, Cu₂O, CuO and CaO). and the effects of composite on the impact strength, flexural strength and surface hardness of the reinforced poly-DCPD type epoxy resin were experimentally examined.<BR> Impact strength and flexural strength increased as the amount of SiO₂ added increased. but decreased at more than 0.6wt%. also surface hardness showed a constant value regardless of the addition amount. and impact strength and flexural strength increased as the size of SiO₂ particles was smaller. it was found that the surface hardness had little effect.<BR> The impact strength, flexural strength and surface hardness were highest when Cu₂O was used as a filler. SiO₂ and CuO were similar to each other. and the curing temperature was increased, impact strength, flexural strength and surface hardness did not changed.

Investigation of the specific adhesion between polyurethane foams and thermoplastics to suited material selection in lightweight structures

Lightweight construction combines various materials to create resource efficient components. Thermoplastics (TPs) combined with polyurethane (PUR) foams are increasingly used to create hybrid composites. Optimizing the energy efficiency is one of the main issues in the development of production processes of components. Reducing the number of process steps offers great potential in this respect. PUR foam develops a strong adhesive bond with most materials. This is used for the manufacturing of hybrid composite components by filling complex cavities with PUR foam simultaneously bonded with other TP polymer components. This way, one process step for joining is saved. The interfaces in this composite structures are critical points of the failure. A huge variety of TP is used for the production of hybrid composite components and PUR foam develops varying bonding strengths with all of them. Selecting the suitable TPs for a durable bonding with PUR foam in the desired production process necessarily requires information about the respective specific adhesion. In this investigation, different TPs were processed with PUR foams in order to manufacture sandwich composites. The TP facings are produced in the injection moulding process. Subsequently, the facings are combined with the foam core during reaction injection moulding. The wetting behaviour was examined using the contact angle measurement and the mechanical strength of the interface in the sandwich composite was determined using a tensile test. A precise order of the selected TPs concerning their specific adhesion to PUR foams was achieved with these investigative methods.

Elaboration of nanostructured polyurethane foams/OMMT using a twin-screw extruder in counter-rotating mode

In this work, a new elaboration method for nanostructured foam polyurethane/ organo-modified montmorillonite (PUR/OMMT) by in situ polymerization is proposed. A twin-screw extruder in the contra-rotation mode combined with reaction injection molding (RIM) as the polymerization process was used. The blended polyols, copolymer polyol (CPP) were included between the OMMT layers via the twin-screw extruder. Both the formulation of the PUR and the inter-foliar distance in the montmorillonite (MMT) were optimized. The effect of some parameters such as OMMT content and catalyst (triethylenediamine for PUR 3 and triethylenediamine+diamino-1,2 propane for PUR 4) was also investigated. The synthesized materials (OMMT, PUR and PUR/OMMT) were characterized by different methods, i.e., Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of evaluation tests, such as flammability and the tensile for the PUR 3+OMMT foams revealed that the optimum properties were obtained for PUR 3+2 % OMMT. The PUR 4 foam showed better mechanical and flame- -retardant properties than the PUR 3 (r = ?NCO/?OH = 1.15) foam. However, the PUR 4 + 2 % OMMT formula exhibited the most delayed flame diffusion and pronounced rigidity.

The Use of Reactions of Metathesis Polymerisation of Cyclic Olefins for the Production of a Dicyclopentadiene Polymer

The results of a literature study of methods for producing polydicyclopentadiene (PDCPD) by the metathesis polymerisation of cycloolefins are given. Approaches to forming the components of the catalytic system are studied with the aim of creating a process for the production of PDCPD by reaction injection moulding technology using as far as possible Nizhnekamskneftekhim's own raw material. The present state and the prospects of the industrial production and consumption of PDCPD in Russia and in member countries of the CIS are considered.

LABORATORY-SCALE REACTION INJECTION MOLDING OF POLY(CAPROLACTONE) ELASTOMERS FOR RAPID PROTOTYPING OF STIMULI-RESPONSIVE THERMOSETS

ABSTRACT Semicrystalline polymer networks offer valuable shape-memory and shape-shifting properties; however, material processing and scale-up remain major challenges. A laboratory-scale reaction injection molding (RIM) apparatus and methodology are described to mold and cure urethane linked poly(caprolactone) networks from commercially available polyols and polyisocyanate. The highly customized RIM system is capable of making small shot sizes (∼39 g) at precise stoichiometric ratios and forming elastomers with low run-to-run variation of mechanical properties. Experiments conducted with a dye in one feed stream enable evaluation of mixing efficacy, and component mixing is substantially improved by recirculating reagents at higher pressures. Networks prepared with excess isocyanate exhibited higher modulus, which is most likely due to the formation of allophanates.