Include your own module in another Angular 5

My question is: How can I import Angular material modules into a proper module, and then import that module into app.module.ts?

This is my personal module:

import { NgModule } from '@angular/core';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { MatMenuModule } from '@angular/material/menu';
import { MatButtonModule } from '@angular/material/button';

@NgModule({
    imports: [
        BrowserAnimationsModule,
        MatMenuModule,
        MatButtonModule
    ],
    declarations: [

    ]
})

export class MaterialModule { }

with which what I do is the following in app.module.ts:

import {MaterialModule} from './material.module';

import array:

imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule,
    FormsModule,
    MaterialModule
  ],

The thing is that I get errors, but if I do it directly everything in app.module.ts works for me. I don't want to have everything imported in the same module, so as not to make it difficult when reviewing or correcting code. Thanks in advance, regards.