Chemical Analyses of Palm Kernel Oil-Based Polyurethane Prepolymer

Polyurethane (PU) was prepared from palm kernel oil-based monoester polyol (PKO-p) via prepolymerization method at NCO/OH ratio of 200/100, 150/100, 100/100, and 75/100 at ambient temperature under nitrogen gas atmosphere. The structure of the synthesized prepolymerized PKO-p PU was determined using FTIR and 13C NMR. The disapperance of NCO peak in the FTIR spectrum at 2270 cm–1 - 2250 cm–1 cm showed that MDI has completely reacted to form PU. The appearance of C=O peak at 1700 cm–1 indicated that hydrogen bonding was formed between the soft segmented chain of the PKO-p and the hard segmented MDI. Hence, urethane bond was the main polymeric chain in the PU.

Synthesis of a Novel UV-curable Prepolymer Polypropyleneglycol Diglycidyl Ether Diacrylate

A novel UV-curable prepolymer polypropyleneglycol diglycidyl ether diacrylate （PPGGEA） was synthesized by utilizing polypropyleneglycol diglycidyl ether （PPGGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were in the following： the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ~C, and the molar ratio of PPGGE to AA was 1：2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized PPGGEA to prepare a kind of UV-cured coating. The mechanical properties of the UV-cured films were determined, giving 29.99 MPa of tensile strength, 834.27 MPa of the Young＇s modulus and 5.66% of elongation at tear.

Preparation and Characterization of Phenolic Prepolymer Impregnated Chinese Fir by Cyclic Increasing-Pressure Method with Green and Efficient

The Chinese fir wood was impregnated using a cyclic increasingpressure method(CIPM)with phenolic prepolymers as the impregnating modifier.Unmodified Chinese fir and progressive increasing-pressure method(PIPM)impregnated Chinese fir were used as reference samples and were compared and analyzed.The product’s chemical structure,internal morphology,crystal structure,and heat resistance were characterized.The transversal and longitudinal sections showed better filling effects,so that it bore greater external loading and reduced the water storage space.CIPM infused more phenolic prepolymer into the Chinese fir.Not only producing more physical filling but also forming more hydrogen bond associations and chemical bond combinations.Compared with PIPM and unmodi-fied Chinese fir,the CIPM impregnated Chinese fir had better mechanical strength and water resistance.The cellulose chains in CIPM impregnated Chinese fir were more closely linked and their crystallinity were clearly improved.Changes in internal morphology and crystal structure explained the reason why the mechanical properties and water resistance of CIPM impregnated Chinese fir were improved significantly.This Chinese fir had lower thermal decomposition rates,higher decomposition residual rates,and smaller combustion flames,which confirmed that it possessed improved heat and fire resistance.

Synthesis of a Novel UV-curable Prepolymer Hexanediol Diglycidyl Ether Diacrylate and Its Cured Film Tensile Property

A novel UV-curable prepolymer hexanediol diglycidyl ether diacrylate （HDGEA） was synthesized by utilizing hexanediol diglycidyl ether （HDGE） and acrylic acid （AA） as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimal synthetic conditions were that the concentration of N, N-dimethylbenzylamine was 0.80 wt% of reactants, the concentration of p-hydroxyanisole was 0.3 wt% of reactants, the reaction temperature was 90-110 ℃, and the molar ratio of HDGE to AA was 1︰2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-curing initiator was added to the synthesized HDGEA to prepare a kind of UV-curing coating. The mechanical properties of the UV-cured films were determined, giving 31.87 MPa of tensile strength, 871.88 MPa of Young＇s modulus and 6.77% of elongation at tear.

Performance of CTBN(carboxyl-terminated poly (butadiene-co-acrylonitrile))-EP(diglycidyl ether of bisphenol-A (DGEBA)) Prepolymers and CTBN-EP/polyetheramine (PEA) System

CTBN-EP prepolymers were synthesized from CTBN and epoxy resin under the catalysis of HTMAB. FTIR analyses indicate the formation of ester group between the carboxyl group of CTBN and the oxirane group of epoxy resin. The viscosity of modified prepolymer increases with CTBN content increasing, but the epoxy value of the prepolymer decreases greatly. DSC analyses verify that CTBN affects the curing process of CTBN-EP/PEA system. Mechanical testing presents the improved toughness of CTBN-EP/PEA curings for the decrease of tensile strength, flexural strength and compressive strength, and increase of impact strength and elongation-at-break with the CTBN content increasing. SEM micrographs show the rubber phase with many holes in diameter about 0.5-1.5 μm is formed when CTBN content is lower than 10 phr. However, the pattern of SEM graph shows some stalactite-like strips when CTBN content is higher than 15 phr. Furthermore, the SEM image of 25 phr CTBN sample forms a kind of co-continuous structure.

Improved Polyurethane-coated Orthopedic Casting Bandage for Medical Application

A new improved polyester casting bandage, which comprises a knitted polyester substrate coated with polyurethane prepolymer, was developed. The appropriate polyester knitted substrate was selected firstly; the optimal ingredient for the synthesis of coating resin (polyurethane prepolymer) was determined then through a series of trial experiments and factorial experiments; the properties of bandage were checked at last. The results of the experiment indicate that most of the properties of the new product could exceed or approximate to the level of similar product of other countries.

SYNTHESES OF STYRENE-METHYL METHACRYLATE BLOCK COPOLYMER BY POLYAZOAMIDE AS INITIATOR

Polyazoamide（PAA） was used as initiator to prepare block copolymer P（MMA-b-St） byfree radical polymerization. The fraction of block copolymer was about 50%. The structureof the block-copolymer was characterized by IR and the results of;H-NMR and GPCshowed that the content of the block and the molecular weight （M;） of the prepolymerand block copolymer could be controlled by varying the mol ratio of styrene/PAA andMMA/prepolymer. DSC and TEM results revealed that the block copolymer has twoseparated glass transition temperatures and phase separation within the domain structure.

Synthesis and Properties of Polyurethane Resins from Liquefied Benzylated Wood

In this paper, polyurethane resins were synthesized from liquefied benzylated wood and TD1 (toluene diisocyanate)-TMP (trihydromethylene propane) prepolymer. And the relation between microphase structure and properties of PU samples were also studied. The results indicated that coatings obtained had good mechanical and thermal properties. The amount of the curing agent has great effect on the degree of phase segregation. In addition, with increased the curing agent amount, the thermal stabilities were also improved.

Pre-PET Graft Modification of Nano-ZrO_2 and Its Effect on Mechanical Property of PC Composites

Nano-ZrO2 particles were modified by poly(ethylene terephalate) prepolymer(pre-PET) via polycondensation.FT-IR,TEM,and TGA results showed that pre-PET was successfully grafted on the surface of nano-ZrO2particles.Compared to the original nano-ZrO2,the grafted nano-ZrO2 had better compatibility with the polycarbonate(PC) matrix and could be dispersed more homogeneously in PC.Hence,interfacial adhesion between ZrO2 and PC was enhanced.The mechanical properties of the resultant PC/nano-ZrO2 composite like tensile strength and notched impact strength were greatly improved.Calculated respectively from tensile yield stress PC/nano-ZrO2 composites,the interfacial interaction parameter B was employed to quantitatively characterize the effective interfacial interaction between the nano-ZrO2 and PC matrix.

Synthesis of a novel UV-curable prepolymer neopentyl glycol diglycidyl ether diacrylate and its cured film tensile property

A novel UV-curable prepolymer neopentyl glycol diglycidyl ether diacrylate (NPGGEA) was synthesized by using neopentyl glycol diglycidyl ether (NPGGE) and acrylic acid (AA) as starting materials, N, N-dimethylbenzylamine as catalyst and p-hydroxyanisole as inhibitor. The optimum synthetic conditions were taken as follows: The concentration of N,N-dimethylbenzylamine, 0.80% of reactants; the concentration of p-hydroxyanisole, 0.3% of reactants; the reaction temperature, 90-110 ; the molar ratio of NPGGE to AA, 1:2.2. Meanwhile, 1-hydroxycyclohexyl phenyl ketone of a UV-cured initiator was added to the synthesized NPGGEA to prepare a kind of UV-cured coating. Mechanical properties of the UV-cured films were determined, giving 28.75 MPa of tensile strength, 923.82 MPa of Young’s modulus and 5.51% of elongation at tear.

The Synthesis of Poly(ethylene oxide)-Block-Polybutylacrylate

Poly(ethylene oxide) containing azogroups(pre PEO) was prepared by reacting azoisobutyronitrile (AIBN) with poly( ethylene glycol ) (PEG). The molecular weight of pre PEO was depended on the reaction time, the ratio of PEG to AIBN and the molecular weight of PEG. Pre PEO decomposed in the presence of butylacrylate (BA) monomer to form poly ethylene oxide block butylacrylate copolymers(PEO b PBA). The molecular weights of PEO b PBA and the homopolymer of PBA were proportional to the ratio of BA to pre PEO. The purified block copolymers were charactherized using IR, 1H NMR and GPC.