The Research On The Construction And The Performance Of Macromolecule Hole-Opened Type Multi-Hole Material

Macromolecule hole—opened type multi — hole material which is macro — hole compound material made up of macromolecule and gas, belongs to the category of vesicant materials. Macromolecule hole —opened type multi— hole material has excellent performance of absorption and penetration due to its function of capillary vessel. Besides, it also has the characteristics of lightness , good heat insulation and sound insulation, as well as high mechanical strength. And it can be used for manufacturing products of any shape in large volume, in addition, it can also be processed mechanically such as, cutting and turning and can also be processed thermally such as, flexing and welding.According to its hole diameter, macromolecule hole — opened type multi— hole material can be divided: Extreme macro—hole material, super macro —hole material, macro — hole material and general macro —hole material and thedensity of macro — hole material can be reduced by 5 % ~ 98% than that before being frothed; The macro hole can be able to slow the stress concentration inside material while the free volume and defects in polymer can be replaced, which can optimize the performance of material and improve the anti—impact capability of material, widely used as material for filtration, sound absorption^ sedimentation and so on, emphasized more and more in biological medicine project.The nucleation mechanism of macromolecule hole — opened type multi— hole material is mainly based on the mechanism "Hotspot nucleation mechanism" raised by R. H. Hansen, W. M MARTIN, C. J. BENNNING, L. L. BLYLER. The main thesis of this mechanism is "lots of bubble nucleus dispersed equally must be formed in the melting body of polymer and lots of hotspots that the su-persaturation gas dispersed largely in the melting body of polymer at the same time, which is the two prerequisites of hotspot nucleation. Working as the hotspot nucleation pharmaceutical, its caloric value^418 6J/G and its decom-position speed, decomposition temperature, grain size and its decomposition character in melting body will all affect its nucleation rate, and in the same condition, the density of nucleation pharmaceutical will increase 10 times, quantity of bubble will increase 4 times and the volume of each bubble will reduce 1/50 of the former one.1. The increase of amount used for vesicant will make the quantity of bubble holes of rubber and plastic maromol-ecule material increased and the volume reduced, which can improve the tensile strength and breakage and tensile rate; Although flexural modulus also changed, not obvious. We could choose the proper amount of vesicant according to this regulation and the performance requirement of product and of the amount is too large for it to achieve its function existing in product.2. The increase if nucleation pharmaceutical also can make the quantity of bubble holes of rubber and plastic maromolecule material increased and the volume reduced, and improve the steel character of material meanwhile decline the tensile strength of material. Although the additionof nucleation pharmaceutical can reduce the cost of product , if more added it will result in poor performance of material, so we must consider the above elements while considering the amount used.3. The addition of nucleation pharmaceutical improve the vitrification transformation temperature of material, and increase the energy storage modulus E of bubble; the addition of vesicant also improve the vitrification transformation temperature of material, due to the existence of bubble hole. Through the influence regulation of vesicant on the consuming gene, we know frothing mainly happen in plastic * * * * * *4. During the process of squeezing operation, we must pay more attention to the enactment of the temperature for equally —mixing period and the head of squeezing machine. Poor enactment will make vesicant unable to function. The temperature at equally — mixing period must be enacted at the low temperature period of the temperature zone for vesicant decomposing. Overlow, vesicant won' t decompose; Overhigh, bubble hole will sink^ crack and gas escape,unable to form more equal bubble holes and the declination of steel character. The temperature of squeezing machine head must be a little higher that that of vesicant, meanwhile, the higher of temperature of squeezing machine head, the better of bubble hole will grow and it is possible to get higher steel character, but if overhigh for the temperature of machine head, the steel character of material will be reduced. The size of bubble hole and steel character of material is mainly controlled through controlling the temperature of machine head.During the frothing process of squeezing out, the accurate controlling for temperature is a most important measure that limit the loss of gas. Inside the machine head we must make the mucosity of melting body low enough to keep good fluid and as well we should also make the mucosity of melting body high enough to keep the high pressure of melting body inside the machine head to make it not froth in machine head. While the temperature inside the machine head will impact the mucosity of melting body inside the machine head and then influence frothing.If the temperature for machine head overhigh, the strength of melting body will be reduced, which will lead to the low pressure of machine head unable to keep gas and the bubble hole intend to unite or sink resulting small quantity of bubble hole; Overlow, the bubble holes we get will have small size, thin wall, equal and fine bubble hole and high rate of frothing. But if temperature overlow, production rate will low, the mucosity on surface overhigh, cutting function overlarge, melting body broken and quality impacted.In addition, during the frothing process of squeezing out, under certain prescription, the mouth shape of machine head and its temperature, the rotation speed of screw have beat value; The more the shape of machine head tend to set up high pressure, the bubble hole of bubbles produced will be more fine and equal and have high frothing rate. Under the condition that they are squeezed out smoothly, the lower the mould at the mouth of machine head, the easier it is to get bubbles with high frothing rate.The molding process of macromolecule multi — hole...